On some Leibniz algebras, having small dimension

The first step in the study of all types of algebras is the description of such algebras having small dimensions. The structure of 3-dimensional Leibniz algebras is more complicated than 1 and 2-dimensional cases. In this paper, we consider the structure of Leibniz algebras of dimension 3 over the f...

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Published in:Algebra and Discrete Mathematics
Date:2019
Main Author: Yashchuk, V.S.
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Language:English
Published: Інститут прикладної математики і механіки НАН України 2019
Online Access:https://nasplib.isofts.kiev.ua/handle/123456789/188439
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Journal Title:Digital Library of Periodicals of National Academy of Sciences of Ukraine
Cite this:On some Leibniz algebras, having small dimension / V.S. Yashchuk // Algebra and Discrete Mathematics. — 2019. — Vol. 27, № 2. — С. 292–308. — Бібліогр.: 16 назв. — англ.

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citation_txt On some Leibniz algebras, having small dimension / V.S. Yashchuk // Algebra and Discrete Mathematics. — 2019. — Vol. 27, № 2. — С. 292–308. — Бібліогр.: 16 назв. — англ.
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container_title Algebra and Discrete Mathematics
description The first step in the study of all types of algebras is the description of such algebras having small dimensions. The structure of 3-dimensional Leibniz algebras is more complicated than 1 and 2-dimensional cases. In this paper, we consider the structure of Leibniz algebras of dimension 3 over the finite fields. In some cases, the structure of the algebra essentially depends on the characteristic of the field, in others on the solvability of specific equations in the field, and so on.
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fulltext “adm-n2” — 2019/7/14 — 21:27 — page 292 — #142 Algebra and Discrete Mathematics RESEARCH ARTICLE Volume 27 (2019). Number 2, pp. 292–308 c© Journal “Algebra and Discrete Mathematics” On some Leibniz algebras, having small dimension Viktoriia S. Yashchuk Communicated by L. A. Kurdachenko Abstract. The first step in the study of all types of algebras is the description of such algebras having small dimensions. The structure of 3-dimensional Leibniz algebras is more complicated than 1 and 2-dimensional cases. In this paper, we consider the structure of Leibniz algebras of dimension 3 over the finite fields. In some cases, the structure of the algebra essentially depends on the characteristic of the field, in others on the solvability of specific equations in the field, and so on. Introduction Let L be an algebra over finite field F with the binary operations + and [·, ·]. Then L is called a Leibniz algebra (more precisely a left Leibniz algebra) if it satisfies the (left) Leibniz identity [[a, b], c] = [a, [b, c]]− [b, [a, c]] for all a, b, c ∈ L. We will also use another form of this identity: [a, [b, c]] = [[a, b], c] + [b, [a, c]]. The author would like to express her sincere thanks to her scientific advisor Professor L. A. Kurdachenko. 2010 MSC: 17A32, 17A60. Key words and phrases: Leibniz algebra, ideal, factor-algebra, Leibniz kernel, finite dimensional Leibniz algebra, nilpotent Leibniz algebra, left (right) center, Frattini subalgebra. “adm-n2” — 2019/7/14 — 21:27 — page 293 — #143 V. S. Yashchuk 293 Leibniz algebras appeared first in the papers of A.M. Bloh [5–7], in which he called them the D-algebras. However, in that time these works were not in demand, and they have not been properly developed. Only after two decades, a real interest to Leibniz algebras rose. It happened thanks to the work of J.-L. Loday [15] (see also [16, Section 10.6]), who “rediscovered” these algebras and used the term Leibniz algebras since it was Gottfried Wilhelm Leibniz who discovered and proved the Leibniz rule for differentiation of functions. Let L be a Leibniz algebra over finite field F . If A,B are subspaces of L, then [A,B] will denote a subspace generated by all elements [a, b] where a ∈ A, b ∈ B. As usual, a subspace A of L is called a subalgebra of L, if [x, y] ∈ A for every x, y ∈ A. It follows that [A,A] 6 A. Let L be a Leibniz algebra over finite field F , M be non-empty subset of L, then 〈M〉 denote the subalgebra of L generated by M . A subalgebra A of L is called a left (respectively right) ideal of L, if [y, x] ∈ A (respectively [x, y] ∈ A) for every x ∈ A, y ∈ L. In other words, if A is a left (respectively right) ideal, then [L,A] 6 A (respectively [A,L] 6 A). A subalgebra A of L is called an ideal of L (more precisely, two-sided ideal) if it is both a left ideal and a right ideal, that is [y, x], [x, y] ∈ A for every x ∈ A, y ∈ L. If A is an ideal of L, we can consider a factor-algebra L/A. It is not hard to see that this factor-algebra also is a Leibniz algebra. As usual, a Leibniz algebra L is called abelian if [x, y] = 0 for all elements x, y ∈ L. In abelian Leibniz algebra every subspace is a subalgebra and an ideal. Denote by Leib(L) the subspace, generated by the elements [a, a], a ∈ L. It is possible to prove that Leib(L) is an ideal of L such that L/Leib(L) is a Lie algebra. Conversely, if H is an ideal of L such that L/H is a Lie algebra, then Leib(L) 6 H. The ideal Leib(L) is called a Leibniz kernel of algebra L. We note a following important property of Leibniz kernel: [[a, a], x] = [a, [a, x]]− [a, [a, x]] = 0. This property shows that Leib(L) is an abelian subalgebra of L. As usual, we say that a Leibniz algebra L is finite dimensional, if the dimension L as a vector space over F is finite. The first step in the study of all types of algebras is the description of such algebras having small dimensions. “adm-n2” — 2019/7/14 — 21:27 — page 294 — #144 294 On some Leibniz algebras, having small dimension If dimF (L) = 1, then L is an abelian Lie algebra, that is L = Fa for some element a and [a, a] = 0. If dimF (L) = 2 and L is not a Lie algebra, then there are the following two non-isomorphic Leibniz algebras: L1 = Fa+ Fb, [a, a] = b, [b, a] = [a, b] = [b, b] = 0, and L2 = Fc+ Fd, [c, c] = [c, d] = d, [d, c] = [d, d] = 0. (see, for example, a survey [12]). The structure of 3-dimensional Leibniz algebras is more complicated. The study of Leibniz algebras, having dimension 3, has been conducted in the papers ([1,2,8,10]) for the fields of characteristic 0, moreover for a field C of complex numbers or algebraically closed field of characteristic 0. In this paper, we consider the opposite situation, where the structure of Leibniz algebras of dimension 3 over the finite field will be described. As we will see later, the situation here is much more diverse, in some cases the structure of the algebra essentially depends on the characteristic of the field, in others on the solvability of specific equations in the field, and so on. We will see that the Leibniz algebras of dimension 3 is soluble, therefore a first natural step of our study is a consideration of nilpotent algebras. Let L be a Leibniz algebra. Define the lower central series L = γ1(L) > γ2(L) > . . . γα(L) > γα+1(L) > . . . γδ(L) of L by the following rule: γ1(L) = L, γ2(L) = [L,L], and recursively γα+1(L) = [L, γα(L)] for all ordinals α and γλ(L) = ⋂ µ<λ γµ(L) for the limit ordinals λ.It is possible to shows that every term of this series is an ideal of L. The last term γδ(L) is called the lower hypocenter of L. We have γδ(L) = [L, γδ(L)]. If α = k is a positive integer, then γk(L) = [L, [L, [L, . . .] . . .]]. A Leibniz algebra L is called nilpotent if there exists a positive integer k such that γk(L) = 〈0〉. More precisely, L is said to be nilpotent of nilpotency class c if γc+1(L) = 〈0〉, but γc(L) 6= 〈0〉. We denote by ncl(L) the nilpotency class of L. The left (respectively right) center ζ left(L) (respectively ζright(L)) of a Leibniz algebra L is defined by the rule: ζ left(L) = {x ∈ L| [x, y] = 0 for each element y ∈ L} “adm-n2” — 2019/7/14 — 21:27 — page 295 — #145 V. S. Yashchuk 295 (respectively, ζright(L) = {x ∈ L| [y, x] = 0 for each element y ∈ L}). It is not hard to prove that the left center of L is an ideal, but it is not true for the right center. Moreover, Leib(L) 6 ζ left(L), so that L/ζ left(L) is a Lie algebra. The right center is a subalgebra of L, and in general, the left and right centers are different; they even may have different dimensions. The corecponding examples could be find in [13]. Of course we will consider a case when L is a not Lie algebra. 1. Nilpotent Leibniz algebra of dimension 3 In this section we will suppose that L is nilpotent. Since ncl(L) 6 dimF (L), ncl(L) 6 3. Let L be a Leibniz algebra over field F . The intersection of the maximal subalgebras of L is called the Frattini subalgebra of L and de- noted by Frat(L). If L does not include maximal subalgebras, then put L = Frat(L). We will need the following important property of Frattini subalgebras. Proposition 1. Let L be a finite dimensional Leibniz algebra over finite field F . If L is nilpotent then [L,L] = Frat(L). Indeed since L is nilpotent, every maximal subalgebra of L is an ideal [3, Lemma 2.2], so we can apply Proposition 7 of paper [12]. Theorem 1. Let L be a nilpotent Leibniz algebra over finite field F . If L is a not Lie algebra and ncl(L) = 3 = dimF (L), then L has a basis {a, b, c} such that [a, a] = b, [a, b] = c, [c, a] = [a, c] = [b, a] = [c, b] = [b, c] = [b, b] = [c, c] = 0. Moreover, Leib(L) = ζ left(L) = [L,L] = Fb ⊕ Fc, ζright(L) = ζ(L) = γ3(L) = Fc. In particular, L is a nilpotent cyclic Leibniz algebra. Proof. Since γ1(L) = L 6= γ2(L) = [L,L] 6= γ3(L) 6= 〈0〉, dimF (γ2(L)) = 2, dimF (γ3(L)) = 1 = dimF (L/γ2(L)). Let a be an element of L such that a /∈ γ2(L). Then Proposition 1 shows that L is a cyclic algebra, generated by an element a. Put b = [a, a], then b ∈ γ2(L) = [L,L] and b ∈ Leib(L). It follows that [b, a] = 0. If we suppose that [a, b] = 0, then b ∈ ζ(L). But in this case γ2(L) 6 ζ(L) and γ3(L) = 〈0〉, that contradicts to our assumption. Thus [a, b] = c 6= 0. Then c ∈ γ3(L), that follows that γ3(L) = Fc and [c, a] = [a, c] = [c, b] = [b, c] = 0. “adm-n2” — 2019/7/14 — 21:27 — page 296 — #146 296 On some Leibniz algebras, having small dimension The case when ncl(L) = 2 break up on two subcases. First: there exists an element d /∈ γ2(L) = [L,L] such that [d, d] = 0. Second: [d, d] 6= 0 for each element d /∈ γ2(L). In the second case [d, d] is a non-zero element of ζ(L). Then ζ(L) = F [d, d] 6 〈d〉. Since a factor-algebra L/ζ(L) is abelian, a cyclic subalgebra 〈d〉 is an ideal. Then and every non-zero subalgebra of L is an ideal. The following two theorems consider the both these subcase separately. Further writing L = A ⊕ B means that L is a direct sum of the subspaces A and B or the subalgebras A and B. If L = A⊕B and A is an ideal of L and B is a subalgebra of L, then we will say that L is a semidirect sum of A and B and use the following symbol L = A ⊣ B. Theorem 2. Let L be a nilpotent Leibniz algebra over finite field F . Suppose that L is a not Lie algebra, dimF (L) = 3, ncl(L) = 2 and L has an element b /∈ γ2(L) such that [b, b] = 0. Then L is an algebra of one of the following types: I. L = A ⊕ B, where A, B are the ideals, B = Fb, [b, b] = 0, A = Fa⊕ Fc is a cyclic nilpotent subalgebra, [a, a] = c, [c, a] = [a, c] = [c, c] = 0. Moreover, Leib(L) = [L,L] = Fc, ζ left(L) = ζright(L) = ζ(L) = Fb⊕ Fc. II. L = A ⊣ B, where A = Fa ⊕ Fc is a cyclic nilpotent subalgebra, [a, a] = c, [c, a] = [a, c] = 0, B is an abelian subalgebra, B = Fb, [b, b] = 0, and [a, b] = c, [b, a] = [b, c] = [c, b] = [c, c] = 0. Moreover, Leib(L) = [L,L] = ζright(L) = ζ(L) = Fc, ζ left(L) = Fb⊕ Fc. III. L = A ⊣ B, where A = Fa ⊕ Fc is a cyclic nilpotent subalgebra, [a, a] = c, [c, a] = [a, c] = 0, B is an abelian subalgebra, B = Fb, [b, b] = 0, and [a, b] = c, [b, a] = γc, γ 6= 0, [b, c] = [c, b] = [c, c] = 0. Moreover, Leib(L) = [L,L] = ζ left(L) = ζright(L) = ζ(L) = Fc. Proof. Since γ3(L) = 〈0〉, then γ2(L) = [L,L] 6 ζ(L). An inclusion Leib(L) 6 γ2(L) shows that dimF (γ2(L)) > 1. If we assume that dimF (L/γ2(L)) = 1, then Proposition 1 shows that L is a cyclic al- gebra. But in this case it is not hard to prove that dimF (L) = 2. Hence L/γ2(L) is not cyclic, so that dimF (L/γ2(L)) = 2. Put K = γ2(L). Since L is not a Lie algebra, there is an element a such that [a, a] = c 6= 0. An in- clusion K 6 ζ(L) shows that a /∈ K. Since dimF (L/γ2(L)) = 2, K = Fc. The fact that L/K is abelian implies that [a, x], [x, a] ∈ K = Fc 6 〈a〉 for each element x ∈ L. This shows that a subalgebra A = 〈a〉 = Fa⊕Fc is an ideal of L. “adm-n2” — 2019/7/14 — 21:27 — page 297 — #147 V. S. Yashchuk 297 By the choice of an element a we obtain that b /∈ 〈a〉, so that L = A⊕Fb. An equality [b, b] = 0 shows that a subalgebra 〈b〉 is abelian, so that 〈b〉 = Fb. Thus L is a semidirect sum of an ideal 〈a〉 and 1-dimensional abelian subalgebra Fb. Here we will have the following possibilities for commutators [a, b] and [b, a]. (i) [a, b] = [b, a] = 0, in this case a subalgebra 〈b〉 is an ideal and L is a direct sum of two ideals: L = (Fa⊕Fc)⊕Fb, so that L is a Leibniz algebra of type I. (ii) [a, b] = αc, [b, a] = βc, where (α, β) 6= (0, 0). If α 6= 0 (respectively β 6= 0), then we can replace an element b on b1 = α−1b (respectively on b1 = β−1b). Clearly L = 〈a〉 ⊕ Fb1 and [a, b1] = c, [b1, b1] = 0 (respectively [b1, a] = c, [b1, b1] = 0). Consider now two situations, which appear here: (iia) [a, b] = c, [b, a] = 0, (iib) [a, b] = 0, [b, a] = c. In the second case put a1 = a, b1 = a− b, then we have: [b1, b1] = [a− b, a− b] = [a, a]− [b, a]− [a, b] + [b, b] = c− c = 0, [a1, b1] = [a, a− b] = [a, a]− [a, b] = c− 0 = c, [b1, a1] = [a− b, a] = [a, a]− [b, a] = c− c = 0. This shows that in every of situation (iia) and (iib) we come to the same algebra. Thus we obtain the Leibniz algebra of types II and III. In the second subcase we consider a situation when [d, d] is a non-zero element of ζ(L) for each element d /∈ ζ(L). As we noted above, in this case every non-zero subalgebra of L is an ideal. Theorem 3. Let L be a nilpotent Leibniz algebra over finite field F . Suppose that L is a not Lie algebra, dimF (L) = 3, ncl(L) = 2 and [d, d] 6= 0 for each element d /∈ γ2(L). Then L is an algebra of one of the following types: I. L = A+B, where A, B are the nilpotent ideals, A = 〈a〉, B = 〈b〉, A∩B = ζ(L) = Fc, [a, a] = [b, b] = c, [c, a] = [a, c] = [c, b] = [b, c] = [a, b] = [b, a] = [c, c] = 0. Moreover, Leib(L) = [L,L] = ζ left(L) = ζright(L) = ζ(L) = Fc, char(F ) 6= 2, and an equation X2 + 1 = 0 has not a solution in F . II. L = A+B, where A, B are the nilpotent ideals, A = 〈a〉, B = 〈b〉, A ∩ B = ζ(L) = Fc, [a, a] = c, [b, b] = ρc, where ρ is a primitive root of identity of degree |F | − 1, [c, a] = [a, c] = [c, b] = [b, c] = “adm-n2” — 2019/7/14 — 21:27 — page 298 — #148 298 On some Leibniz algebras, having small dimension [a, b] = [b, a] = [c, c] = 0. Moreover, Leib(L) = [L,L] = ζ left(L) = ζright(L) = ζ(L) = Fc, char(F ) 6= 2. III. L = A+B, where A, B are the nilpotent ideals, A = 〈a〉, B = 〈b〉, A ∩ B = ζ(L) = Fc, [a, a] = c = [a, b], [b, b] = ηc, [c, a] = [a, c] = [c, b] = [b, c] = [b, a] = [c, c] = 0. Moreover, Leib(L) = [L,L] = ζ left(L) = ζright(L) = ζ(L) = Fc and a polynomial X2 +X + η has no roots in a field F . Proof. As in Theorem 2 γ2(L) = [L,L] 6 ζ(L), Leib(L) 6 γ2(L), dimF (γ2(L)) = 1, so that dimF (L/γ2(L)) = 2. Put K = γ2(L). Let a /∈ K, then [a, a] = c 6= 0. Since dimF (γ2(L)) = 1, K = Fc. The fact that L/K is abelian implies that [a, x], [x, a] ∈ K = Fc 6 〈a〉 for each element x ∈ L. This shows that a subalgebra A = 〈a〉 = Fa ⊕ Fc is an ideal of L. Choose an element b /∈ 〈a〉. Then the subset {c, a, b} is a basis of L. By our condition [b, b] = ηc and η 6= 0. Consider the elements [a, b] and [b, a]. Suppose first that [a, b] = [b, a] = 0. Since F is finite, G = F\{0} is a cyclic group by multiplication of order q = |F |−1. Suppose that η ∈ G2. Then η = κ2 for some element 0 6= κ ∈ F . Put b1 = κ−1b, then [b1, b1] = [κ−1b, κ−1b] = κ−2[b, b] = κ−2ηc = κ−2κ2c = c. In particular, if char(F ) = 2, then G2 = G. We take an arbitrary element d = λa+ µb1, where λ 6= 0, µ 6= 0 and find [d, d]. By such choice d /∈ ζ(L), so that [d, d] 6= 0. We have [d, d] = [λa+ µb1, λa+ µb1] = λ2[a, a] + λµ[b1, a] + λµ[a, b1] + µ2[b1, b1] = λ2c+ µ2c. Suppose that λ2 + µ2 = 0. Since µ 6= 0, we obtain y2 + 1 = 0 where y = λµ−1. Thus we see that a polynomial X2 + 1 has no roots in a field F . Since in a field F such that char(F ) = 2 a polynomial X2 + 1 has root 1, the characteristic of F must be not 2. Thus we obtain the Leibniz algebras of type I. For example, if F = F5, F13, an equation y2 + 1 = 0 has a solution, if F = F3, F7, F11, an equation y2 + 1 = 0 has not a solution. Thus we can see that the algebras have the same defining relation, but have the different properties. Consider the case when η /∈ G2. Since G is cyclic, then G/G2 is a cyclic group of order 2, so that G = G2 ∪ ρG2, where ρ is a primitive “adm-n2” — 2019/7/14 — 21:27 — page 299 — #149 V. S. Yashchuk 299 root of identity of degree q. Then η = ρκ2 for some element κ ∈ F . Put b1 = κ−1b, then [b1, b1] = [κ−1b, κ−1b] = κ−2[b, b] = κ−2ηc = κ−2ρκ2c = ρc. As we noted above in this case char(F ) 6= 2. Let again d = λa+ µb1, where λ 6= 0, µ 6= 0. We have [d, d] = [λa+ µb1, λa+ µb1] = λ2[a, a] + µ2[b1, b1] = λ2c+ µ2ρc = (λ2 + µ2ρ)c. Suppose that λ2 + µ2ρ = 0. Since µ 6= 0, we obtain y2 + ρ = 0, where y = λµ−1. By the choice ρ is a generator of a multiplicative cyclic group G = F\{0}, so that ρ /∈ G2. Since 〈ρ〉 6 〈−ρ〉, −ρ /∈ G2. It follows that an equation y2 + ρ = 0 has not a solution in F . Then [d, d] 6= 0 for every element d /∈ Fc. As we have seen above in this case every subalgebra of L is an ideal. Thus we come to a Leibniz algebra of type II. Suppose that [b, a] = αc 6= 0. Then α 6= 0. Put b1 = αa − b, then [b1, a] = [αa− b, a] = α[a, a]− [b, a] = αc− αc = 0. Therefore further we will suppose that [b, a] = 0. We have [a, b] = βc for some element β ∈ F . The case when β = 0 we have already considered. Assume therefore that [a, b] = βc 6= 0. Put b1 = β−1b, then [a, b1] = [a, β−1b] = β−1[a, b] = β−1βc = c. Let again d = λa+ µb where λ 6= 0, µ 6= 0. We have [d, d] = [λa+ µb1, λa+ µb1] == λ2[a, a] + λµ[a, b1] + µ2[b1, b1] = λ2c+ λµc+ µ2ηc = (λ2 + λµ+ µ2η)c, where η = [b1, b1]. Suppose that λ2 + λµ+ µ2η = 0. Since µ 6= 0, we obtain an equation y2+y+η = 0 where y = λµ−1. Hence we see that a polynomial X2+X+η has no roots in a field F . Thus we obtain the Leibniz algebra of type III. As we can see, in this last case the properties of the algebra depend on whether the polynomial above has roots in the field F , and this also depends on the choice of the element η. The difference appears even over fields of the same characteristic. So, if F = F2, then for η only one value is possible η = 1. But an equation y2 + y+1 = 0 has no solution in a field F = F2. Hence the respectively algebra has no element d /∈ Fc such that [d, d] = 0. It follows that every subalgebra of L is an ideal. If F = F4 and η = 1, then an equation y2 + y + 1 = 0 has solutions in a field F4. In this case the respectively algebra L has one dimensional subalgebra, which is no ideal. “adm-n2” — 2019/7/14 — 21:27 — page 300 — #150 300 On some Leibniz algebras, having small dimension 2. Non-nilpotent Leibniz algebras of dimension 3 with 1-dimensional Leibniz kernel over finite fields The next step is a consideration of a case when L is non-nilpotent. We will consider a Leibniz algebras of dimension 3 over finite fields, which are not Lie algebras. It follows that Leib(L) 6= 〈0〉. Since Leib(L) is an abelian ideal, L 6= Leib(L). Hence for Leib(L) we have only two possibility: dimF (Leib(L)) = 1, dimF (Leib(L)) = 2. In this section we consider the case when dimF (Leib(L)) = 1, so that dimF (L/Leib(L)) = 2. Theorem 4. Let L be a non-nilpotent Leibniz algebra over finite field F . Suppose that L is a not Lie algebra, dimF (L) = 3 and dimF (Leib(L)) = 1. Then L is an algebra of one of the following types: I. L = A⊕B, where A, B are the ideals, B = Fb, [b, b] = 0, A is a cyclic subalgebra, A = Fa ⊕ Fc, where [a, a] = c = [a, c], [c, a] = [c, b] = [b, c] = [a, b] = [b, a] = [c, c] = 0. Moreover, Leib(L) = [L,L] = Fc, ζ left(L) = Fb⊕ Fc, ζright(L) = ζ(L) = Fb. II. L = A ⊣ B, where B = Fb, [b, b] = 0, A = Fa ⊕ Fc is a cyclic subalgebra, [a, a] = c = [a, c], [a, b] = c, [c, a] = [c, b] = [b, c] = [b, a] = [c, c] = 0. Moreover, Leib(L) = [L,L] = Fc, ζ left(L) = Fb⊕ Fc, ζ(L) = ζright(L) = 〈0〉. III. L = A ⊣ B, where B = Fb, [b, b] = 0, A = Fa ⊕ Fc is a cyclic subalgebra, [a, a] = c = [a, c], [b, a] = [b, c] = c, [c, a] = [c, b] = [a, b] = [c, c] = 0. Moreover, Leib(L) = [L,L] = ζ left(L) = Fc, ζright(L) = Fb, ζ(L) = 〈0〉. IV. L = A ⊣ B,, where B = Fb, [b, b] = 0, A = Fa ⊕ Fc is a cyclic subalgebra, [a, a] = c = [a, c], [a, b] = a = −[b, a], [b, c] = −2c, [c, a] = [c, b] = [c, c] = 0. Moreover, Leib(L) = [L,L] = ζ left(L) = Fc, ζright(L) = ζ(L) = 〈0〉. V. L = A ⊣ B, where B = Fb, [b, b] = 0, A = Fa ⊕ Fc is a cyclic subalgebra, [a, a] = c, [a, c] = 0, [a, b] = a+γc, γ ∈ F , [b, a] = −a+γc, [b, c] = −2c, [c, a] = [c, b] = 0. Moreover, Leib(L) = [L,L] = ζ left(L) = Fc, ζright(L) = ζ(L) = 〈0〉 whenever char(F ) 6= 2 and ζright(L) = ζ(L) = Fc whenever char(F ) = 2. Proof. Since L is not Lie algebra, there is an element a such that [a, a] = c 6= 0. Then c ∈ K = Leib(L), so that K = Fc. An inclusion Leib(L) 6 ζ left(L) implies that [c, y] = 0 for each element y ∈ L, in particular, [c, a] = 0. A subalgebra 〈a〉 has dimension 2, therefore either [a, c] = 0 or [a, c] = c (see, for example, a survey [12]). Suppose that a Lie algebra L/K “adm-n2” — 2019/7/14 — 21:27 — page 301 — #151 V. S. Yashchuk 301 is abelian and let first [a, c] = 0. Also assume that there is an element b /∈ 〈a〉 such that [b, b] = 0. The fact that L/K is abelian implies that [a, b], [b, a] ∈ Fc. If [a, b] = 0 = [b, a], then a subalgebra 〈b〉 = Fb is an ideal and L is a direct sum of two subalgebras: L = (Fa⊕Fc)⊕Fb. Since L is non-nilpotent, then for [a, c] only one variant remains: [a, c] = c. Thus we obtain the Leibniz algebra of type I. Let now [a, b] = αc, [b, a] = βc, where (α, β) 6= (0, 0). If α 6= 0 (respectively β 6= 0), then we can replace an element b on b1 = α−1b (respectively on b1 = β−1b). Clearly L = 〈a〉 ⊕ Fb1 and [a, b1] = c, [b1, b1] = 0 (respectively [b1, a] = c, [b1, b1] = 0). Consider further all three situation, which appear here. (a) Suppose that [a, b] = c, [b, a] = 0. Then [b, c] = [b, [a, a]] = [[b, a], a] + [a, [b, a]] = 0. If we assume that [a, c] = 0, then K 6 ζ(L), which follows that an algebra L is nilpotent. This situation was considered early. Thus we obtain the Leibniz algebra of type II. (b) Suppose that [a, b] = 0, [b, a] = c. Then [b, c] = [b, [a, a]] = [[b, a], a] + [a, [b, a]] = [c, a] + [a, c] = [a, c]. If we assume that [a, c] = 0, then K 6 ζ(L), so we again come to nilpotent case. Thus we obtain the Leibniz algebra of type III. (c) Suppose that [a, b] = c, [b, a] = βc, where β 6= 0. Then [b, c] = [b, [a, a]] = [[b, a], a] + [a, [b, a]] = β[c, a] + β[a, c] = β[a, c]. On the other hand, [b, c] = [b, [a, b]] = [[b, a], b] + [a, [b, b]] = β[c, b] + [a, 0] = 0. If we assume that [a, c] = 0, then K 6 ζ(L), so we again come to nilpotent case. Then an equality [b, c] = β[a, c] implies that β = 0. Thus we obtain a contradiction, which shows that the last case is impossible. Suppose now that [d, d] 6= 0 for each element d /∈ K. It follows that [d, d] is a non-zero element of K. Then K = F [d, d] 6 〈d〉. Since a factor- algebra L/K is abelian, a cyclic subalgebra 〈d〉 is an ideal. If 0 6= d ∈ K, then 〈d〉 = K, in particular, 〈d〉 again is an ideal. Then and every non-zero subalgebra of L is an ideal. But in this case an algebra L must be nilpotent ([14, Theorem A]). This case was considered above. “adm-n2” — 2019/7/14 — 21:27 — page 302 — #152 302 On some Leibniz algebras, having small dimension Assume now that dimF (Leib(L)) = 1 and a Lie algebra L/K is non-abelian. Again there exists an element a such that [a, a] 6= 0. Since L/K is a Lie algebra, [a, a] ∈ K. If we suppose that a + K ∈ ζ(L/K), then an equality dimF (L/K) = 2 implies that L/K is abelian, and we obtain a contradiction. Thus we can find the element y such that K 6= [a+K, y +K]. The fact that L/K is a Lie algebra of dimension 2 implies that L/K 6= [L/K,L/K] (see, for example, [11, Chapter 1, Section 4]). Then dimF ([L/K,L/K]) = 1. Put d = [a, y], then [L/K,L/K] = 〈d + K〉 = D/K. As above d +K /∈ ζ(L/K). We have one of two following possibilities: 〈d+K〉 = 〈a+K〉 or the intersection 〈d+K〉 ∩ 〈a+K〉 is zero. Consider a first possibility, let 〈d+K〉 = 〈a+K〉. Suppose that there exists an element b /∈ D such that [b, b] = 0. Then L = D ⊕ 〈b〉, where a subalgebra 〈b〉 has a dimension one, that is 〈b〉 = Fb. Since c = [a, a] ∈ K, D = Fa ⊕ Fc. Since a + K /∈ ζ(L/K), [a + K, b + K] 6= K, that is [a+K, b+K] = δ(a+K) for some non-zero element δ ∈ F . Put b1 = δ−1b, then [a+K, b1 +K] = [a+K, δ−1b+K] = δ−1[a+K, b+K] = δ−1(d+K) = δ−1δ(a+K) = a+K. Since [b1, b1] = δ−2[b, b] = 0, we can assume further that [a+K, b+K] = a+K. It follows that [a, b] = a+ γc for some element γ ∈ F . Since L/K is a Lie algebra, [b + K, a + K] = −[a + K, b + K] = −a + K, so that [b, a] = −a + γ1c for some element γ1 ∈ F . An inclusion c ∈ Leib(L) implies that [c, x] = 0 for all x ∈ L, in particular, [c, a] = [c, b] = 0. For element [b, c] we obtain: [b, c] = [b, [a, a]] = [[b, a], a] + [a, [b, a]] = [−a+ γ1c, a] + [a,−a+ γ1c] = [−a, a] + [a,−a] = −2c. Further, [[a, b], b] = [a, [b, b]]− [b, [a, b]] = −[b, [a, b]] = −[b, a+ γc] = −[b, a]− γ[b, c] = a− γ1c+ 2γc = a+ (2γ − γ1)c, and [[a, b], b] = [a+γc, b] = [a, b] = a+γc, so that a+(2γ−γ1)c = a+γc, which implies that γ1 = γ. A subalgebra 〈a〉 has dimension 2, therefore we have two cases: (i) [a, c] = 0 and (ii) [a, c] = c (see, for example, a survey [12]). “adm-n2” — 2019/7/14 — 21:27 — page 303 — #153 V. S. Yashchuk 303 If [a, c] = c, then [[b, a], a] = [b, [a, a]]− [a, [b, a]] = [b, c]− [a,−a+ γ1c] = −2c+ [a, a]− γ1[a, c] = −2c+ c− γ1[a, c], and [[b, a], a] = [−a+ γ1c, a] = −c, which implies that −2c+ c− γ1[a, c] = −c, so that γ1 = 0. Hence if [a, c] = c, then we obtain the Leibniz algebra of type IV. If [a, c] = 0, then we obtain the Leibniz algebra of type V. Assume now that [b, b] 6= 0 for each element b /∈ D. As above we can choose an element b /∈ D such that [a+K, b+K] = a+K. It follows that [a, b] = a+ γc for some element γ ∈ F . Since L/K is a Lie algebra, [b+K, a+K] = −[a+K, b+K] = −a+K, so that [b, a] = −a + γ1c for some element γ1 ∈ F . Since [b, b] 6= 0, [b, b] = ηc for some non-zero element η ∈ F . An inclusion c ∈ Leib(L) implies that [c, x] = 0 for all x ∈ L, in particular, [c, a] = [c, b] = 0. For element [b, c] we obtain again [b, c] = [b, [a, a]] = [[b, a], a] + [a, [b, a]] = [−a+ γ1c, a] + [a,−a+ γ1c] = [−a, a] + [a,−a] = −2c. Further, [[a, b], b] = [a, [b, b]]− [b, [a, b]] = [a, ηc]− [b, [a, b]] = η[a, c]− [b, a+ γc] = η[a, c]− [b, a]− γ[b, c] = η[a, c] + a− γ1c+ 2γc = η[a, c] + a+ (2γ − γ1)c. If [a, c] = 0, then [[a, b], b] = a+ (2γ − γ1)c, if [a, c] = c, then [[a, b], b] = a+(η+2γ−γ1)c. On the other hand, [[a, b], b] = [a+γc, b] = [a, b] = a+γc, so that a+ (2γ − γ1)c = a+ γc or a+ (η + 2γ − γ1)c = a+ γc. Thus if [a, c] = 0, then γ1 = γ, if [a, c] = c, then γ1 = η + γ. Furthermore, [[b, a], a] = [b, [a, a]]− [a, [b, a]] = [b, c]− [a,−a+ γ1c] = −2c+ [a, a]− γ1[a, c] = −2c+ c− γ1[a, c] = −c− γ1[a, c]. and [[b, a], a] = [−a + γ1c, a] = −c, which implies that γ1[a, c] = 0. In particular, if [a, c] = c then γ1 = 0. As we have seen above, in this case “adm-n2” — 2019/7/14 — 21:27 — page 304 — #154 304 On some Leibniz algebras, having small dimension γ1 = η + γ, therefore η = −γ. Suppose that [a, c] = c and consider an element a+ b+ c. We have [a+ b+ c, a+ b+ c] = [a, a] + [a, b] + [a, c] + [b, a] + [b, b] + [b, c] = c+ a+ γc+ c− a− γc− 2c = 0. Since a+ b+ c /∈ D, we obtain a contradiction, which shows that a variant when [a, c] = c is impossible. Hence must be [a, c] = 0. Let x = λa+µb+νc be an arbitrary element of L such that x /∈ D, where λ, µ, ν are some elements of F . We have [λa+ µb+ νc, λa+ µb+ νc] = λ2[a, a] + λµ[a, b] + λµ[b, a] + µ2[b, b] + µν[b, c] = λ2c+ λµ(a+ γc) + λµ(−a+ γc) + µ2ηc− 2µνc = (λ2 + 2λµγ + µ2η − 2µν)c. Consider an equation λ2 + 2λµγ + µ2η − 2µν = 0. If F is a finite field of characteristic 2, then we obtain λ2 + µ2η = 0. Put µ = 1, by such choice x /∈ D. An equation λ2 + η = 0 has a solution in a field F , because F = F2. Thus if F is a finite field of characteristic 2, then there exists an element x /∈ D such that [x, x] = 0, and we obtain a contradiction with our assumption. Suppose now that char(F ) 6= 2. The fact that char(F ) 6= 2 implies that an equation 2x = a has a solution 1 2 a for each element a ∈ F . Put λ = µ = 1, so we come to equation 1 + 2γ + η − 2ν = 0. Thus if we put λ = µ = 1, ν = 1 2 (1 + 2γ + η), then x /∈ D and [x, x] = 0, and we again obtain a contradiction. 3. Non-nilpotent cyclic Leibniz algebras of dimension 3 over finite fields The next step is a consideration of a case when L is non-nilpotent or dimF (Leib(L)) = 2. Here there appear two variants: L is a cyclic algebra and L is a non-cyclic algebra. In this section we will consider a case when Leibniz algebra of dimension 3 is cyclic. Theorem 5. Let L be a non-nilpotent cyclic Leibniz algebra of dimension 3 over finite field F . Then L is an algebra of one of the following types: I. L = D ⊣ A, where D = Fd, [d, d] = 0, A = Fa ⊕ Fc is a cyclic nilpotent subalgebra, [a, a] = c, [a, c] = 0, [a, d] = δd, 0 6= δ ∈ F , [c, a] = [c, d] = [c, c] = [d, c] = [d, a] = 0. Moreover, Leib(L) = [L,L] = ζ left(L) = Fd⊕ Fc, ζ(L) = ζright(L) = Fc. “adm-n2” — 2019/7/14 — 21:27 — page 305 — #155 V. S. Yashchuk 305 II. L = D ⊣ B, where B = Fb, [b, b] = 0, D = Fd ⊕ Fc is an abelian subalgebra, [d, d] = [d, c] = [c, d] = [c, c] = 0, [b, c] = d, [b, d] = γd + δd, 0 6= γ, δ ∈ F , [c, b] = [d, b] = 0. Moreover, Leib(L) = [L,L] = ζ left(L) = Fd⊕Fc, ζright(L) = Fb, ζ(L) = 〈0〉. Proof. Since L is cyclic and has dimension 3, L can not be a Lie algebra. Let a be an element of L such that L = 〈a〉. Since L is a not Lie algebra, [a, a] = c 6= 0. Moreover, c ∈ Leib(L) 6 ζ left(L), that implies [c, x] = 0 for all x ∈ L, in particular, [c, a] = 0. Since L/Leib(L) is a cyclic Lie algebra, that dimF (L/Leib(L)) = 1, so that dimF (Leib(L)) = 2. If we assume that [a, c] ∈ Fc, then 〈a〉 = Fa⊕Fc, so that dimF (L) = 2, and we obtain a contradiction. Thus d = [a, c] /∈ Fc, which follows that {c, d} is a basis of K = Leib(L). Again [d, a] = 0. Since K is an abelian subalgebra, [c, c] = [c, d] = [d, d] = [d, c] = 0. Since K is an ideal, [a, d] ∈ K, so that [a, d] = γc+ δd. If γ = 0 = δ, then L is a cyclic nilpotent algebra. This situation was considered early. Suppose now that γ = 0, δ 6= 0, then [a, d] ∈ Fd, which follows that D = Fd is an ideal of L. Put a1 = a−δ−1c, then [a1, a1] = [a− δ−1c, a− δ−1c] = [a, a]− δ−1[a, c] = c− δ−1d = a2, [a1, a2] = [a− δ−11c, c− δ−1d] = [a, c]− δ−1[a, d] = d− δ−1δd = 0, [a1, d] = [a− δ−1c, d] = [a, d] = δd. Thus we can see that a subalgebra A = 〈a1〉 is nilpotent and has dimension 2, D ∩ A = 〈0〉, so that L is semidirect sum of an ideal D of dimension 1 and a nilpotent subalgebra A of dimension 2. Moreover, D 6 ζ left(L), [L,L] = ζ left(L) = Leib(L) = D ⊕ [A,A]. Thus we obtain the Leibniz algebra of type I. Suppose now that if γ 6= 0, δ 6= 0. Thus [a, d] = γ[a, a] + δ[a, c] and 0 = [a, γa+ δc− d]. Put b = a+ γ−1δc− γ−1d, then [a, b] = 0. Further [b, b] = [a+ γ−1δc− γ−1d, b] = [a, b] + [γ−1δc− γ−1d, b] = 0, so that 〈b〉 = Fb. Since [c, b] = [d, b] = 0, Fb = ζright(L). Furthermore [b, c] = [a+ γ−1δc− γ−1d, c] = [a, c] = d, [b, d] = [a+ γ−1δc− γ−1d, d] = [a, d] = γc+ δd. We can see that L is semidirect sum of an abelian ideal Fc⊕Fd of dimen- sion 2 and abelian subalgebra Fb of dimension 1. Moreover, ζ left(L) = Fc⊕ Fd = Leib(L) = [L,L], ζright(L) = Fb. Thus we obtain the Leibniz algebra of type II. “adm-n2” — 2019/7/14 — 21:27 — page 306 — #156 306 On some Leibniz algebras, having small dimension 4. Non-nilpotent Leibniz algebras of dimension 3 with 2-dimensional Leibniz kernel over finite fields The last case of our consideration is the case when L is non-nilpotent, non-cyclic and dimF (Leib(L)) = 2. Then dimF (L/Leib(L)) = 1. In particular, L/Leib(L) is abelian. Theorem 6. Let L be a non-nilpotent non-cyclic Leibniz algebra of di- mension 3 over finite field F . Suppose that L is a not Lie algebra and dimF (Leib(L)) = 2. Then L is an algebra of one of the following types: I. L = A ⊣ D, where D = Fd, [d, d] = 0, A = Fa ⊕ Fc is a cyclic subalgebra, [a, a] = c = [a, c], [a, d] = d, [c, a] = [c, d] = [d, c] = [d, a] = [c, c] = 0. Moreover, Leib(L) = [L,L] = ζ left(L) = Fd⊕Fc, ζ(L) = ζright(L) = 〈0〉. II. char(F ) 6= 2, L = A ⊣ D, where D = Fd, [d, d] = 0, A = Fa⊕Fc is a cyclic subalgebra, [a, a] = c = [a, c], [a, d] = c+ 2d, [c, a] = [c, d] = [d, c] = [d, a] = 0. Moreover, Leib(L) = [L,L] = ζ left(L) = Fd⊕Fc, ζ(L) = ζright(L) = 〈0〉. Proof. Put K = Leib(L). Since L is a not Lie algebra, there is an element a such that [a, a] = c 6= 0. Then a /∈ K, so that L = K ⊕ Fa. An inclusion Leib(L) 6 ζ left(L) implies that [c, y] = 0 for each element y ∈ L, in particular, [c, a] = 0. For an element [a, c] we have the following possibilities: [a, c] = 0, [a, c] ∈ Fc, [a, c] /∈ Fc. Consider the first situation. Choose an element d ∈ K such that K = Fc ⊕ Fd. Since K is abelian, [d, d] = 0 = [c, d] = [d, c]. It follows that c ∈ ζ(L). We have [d, a] = 0 and [a, d] = γc + δd. If γ = 0, then a subalgebra 〈d〉 = Fd is an ideal. In this case we obtain that L = D⊕A, where D = Fd is an abelian ideal, D 6 ζ left(L), A is a nilpotent cyclic subalgebra, A = Fa⊕Fc, where [a, a] = c, [L,L] = D⊕ [A,A] = ζ left(L), is an abelian ideal. Thus we obtain the Leibniz algebra of above considered Type I from Theorem 5. Assume now that γ 6= 0. Put d1 = γ−1d, then [a, d1] = γ−1[a, d] = γ−1(γc+ δd) = c+ δd1. If we suppose that δ = 0, then again L/ζ(L) is abelian and L is nilpotent. This case has been considered above. Therefore we assume that δ 6= 0. We have [a+ d1, a+ d1] = [a, a] + [a, d1] = c+ c+ δd1 = 2c+ δd1. “adm-n2” — 2019/7/14 — 21:27 — page 307 — #157 V. S. Yashchuk 307 If char(F ) = 2, then Fd1 6 〈a+ d1〉, which follows that a ∈ 〈a+ d1〉 and c = [a, a] ∈ 〈a+d1〉. Thus we can see, that in this case L is a cyclic algebra. Suppose that char(F ) 6= 2. Then from δ(a+d1)−[a+d1, a+d1] ∈ 〈a+d1〉, we obtain δa−2c ∈ 〈a+d1〉. It follows that δ2c = [δa−2c, δa−2c] ∈ 〈a+d1〉, Since δ2 6= 0, Fc 6 〈a+ d1〉. In turn out it follows that Fd1 6 〈a+ d1〉, and again we obtain that L is a cyclic. Suppose now that 0 6= [a, c] ∈ Fc. Then a subalgebra 〈a〉 has dimension 2 and is non-nilpotent. Therefore we can suppose that [a, c] = c (see, for example, a survey [12]). Choose an element d ∈ K such that K = Fc⊕Fd. Since K is abelian, [d, d] = 0 = [c, d] = [d, c]. We have [d, a] = 0 and [a, d] = γc + δd. If γ = 0, then a subalgebra 〈d〉 = Fd is an ideal. In this case we obtain that L = D ⊕ A, where D = Fd is an abelian ideal, D 6 ζ left(L), A is a non-nilpotent cyclic subalgebra of dimension 2, A = Fa⊕ Fc, where [a, a] = c = [a, c], [L,L] = D ⊕ [A,A] = ζ left(L), is an abelian ideal. Thus we obtain the Leibniz algebra of type I. Assume now that γ 6= 0. Put d1 = γ−1d, then [a, d1] = γ−1[a, d] = γ−1(γc+ δd) = c+ δd1. If we suppose that δ = 0, then [a, d1] ∈ Fc, which implies that L/Fc is abelian. In turn out it follows that Leib(L) 6 Fc. But in this case dimF (Leib(L)) = 1, and we obtain a contradiction. This contradiction shows δ 6= 0. We have [a+ d1, a+ d1] = [a, a] + [a, d1] = c+ c+ δd1 = 2c+ δd1. If char(F ) = 2, then Fd1 6 〈a + d1〉, which follows that a ∈ 〈a + d1〉 and c = [a, a] ∈ 〈a+ d1〉. Thus we can see, that in this case L is a cyclic algebra. Suppose that char(F ) 6= 2. Then from δ(a+ d1)− [a+ d1, a+ d1] ∈ 〈a+ d1〉, we obtain δa− 2c ∈ 〈a+ d1〉. It follows that (δ2 − 2δ)c = δ2c− 2δc = [δa− 2c, δa− 2c] ∈ 〈a+ d1〉. By above δ 6= 0. If δ 6= 2, then Fc 6 〈a+ d1〉. In turn out it follows that Fd1 6 〈a + d1〉, and again we obtain that L is a cyclic. Suppose that δ = 2, that is [a, d1] = c+ 2d1. Hence, if L is not cyclic, then L is a Leibniz algebra of a type II. Suppose now that [a, c] /∈ Fc. In this case [a, c] = αc + βd besides β 6= 0. We can see that a Leibniz algebra L is cyclic. This case has been considered above. “adm-n2” — 2019/7/14 — 21:27 — page 308 — #158 308 On some Leibniz algebras, having small dimension References [1] S. Albeverio, B.A. Omirov, I.S. Rakhimov, Varieties of nilpotent complex Leibniz algebras of dimension less than five, Comm. Algebra 33 (2005), no. 5, 1575-1585. [2] S.A. Ayupov, B.A. Omirov, On 3-dimensional Leibniz algebras, Uzbek. Math. Zh., 1 (1999), 9-14. [3] D. Barnes, Some theorems on Leibniz algebras, Comm. Algebra 39 (2011), no. 7, 2463-2472. [4] D. Barnes, Schunck Classes of soluble Leibniz algebras, Comm. Algebra 41 (2013), no. 11, 4046-4065. [5] A.M. Bloh, On a generalization of the concept of Lie algebra, Dokl. Akad. Nauk SSSR 165 (1965), no. 3, 471-473. [6] A.M. Bloh, Cartan-Eilenberg homology theory for a generalized class of Lie algebras, Dokl. Akad. Nauk SSSR 175 (1967), no. 8, 824-826. [7] A.M. Bloh, A certain generalization of the concept of Lie algebra, Algebra and number theory. Moskov. Gos. Ped. Inst. Uchen. Zap. 375 (1971), 9-20. [8] J.M. Casas, M.A. Insua, M. Ladra, S. Ladra, An algorithm for the classification of 3-dimensional complex Leibniz algebras, Linear Algebra Appl. 436 (2012), no. 9, 3747-3756. [9] V.A. Chupordya, L.A. Kurdachenko, I.Ya. Subbotin, On some “minimal” Leibniz algebras, J. Algebra Appl. 16 (2017), no. 2. [10] I. Demir, K.C. Misra, E. Stitzinger, On some structures of Leibniz algebras, Recent Advances in Representation Theory, Quantum Groups, Algebraic Geometry, and Related Topics, Contemporary Mathematics, 623 (2014), 41-54. [11] N. Jacobson, Lie algebras, John Wiley: New York, (1962). [12] V.V. Kirichinko, L.A. Kurdachenko, A.A. Pypka, I.Ya. Subbotin, Some aspects of Leibniz algebra theory, Algebra and Discrete Mathematics, V. 24, N.1, (2017), pp.1-33. [13] L.A. Kurdachenko, J. Otal, A.A. Pypka, Relationships between factors of canonical central series of Leibniz algebras, Eur. J. Math. 2 (2016), no. 2, 565-577. [14] L.A. Kurdachenko, N.N. Semko, I.Ya. Subbotin, The Leibniz algebras whose subalgebras are ideals, Open Math. 15 (2017), no. 1, 92-100. [15] J.-L. Loday, Une version non commutative des algèbres de Lie: les algèbras de Leibniz, L’Enseignement Mathèmatique 39 (1993), 269-293. [16] J.-L. Loday, Cyclic homology. Grundlehren der Mathematischen Wissenschaften, Vol. 301, 2nd ed., Springer, Verlag, Berlin, 1998. Contact information V. S. Yashchuk Department of Geometry and Algebra, Faculty of Mechanics and Mathematics, Oles Honchar Dnipro National University, Gagarin ave., 72, Dnipro, 49010,Ukraine E-Mail(s): Viktoriia.S.Yashchuk@gmail.com Received by the editors: 28.02.2018 and in final form 22.03.2018.
id nasplib_isofts_kiev_ua-123456789-188439
institution Digital Library of Periodicals of National Academy of Sciences of Ukraine
issn 1726-3255
language English
last_indexed 2025-12-07T17:47:25Z
publishDate 2019
publisher Інститут прикладної математики і механіки НАН України
record_format dspace
spelling Yashchuk, V.S.
2023-03-01T15:54:47Z
2023-03-01T15:54:47Z
2019
On some Leibniz algebras, having small dimension / V.S. Yashchuk // Algebra and Discrete Mathematics. — 2019. — Vol. 27, № 2. — С. 292–308. — Бібліогр.: 16 назв. — англ.
1726-3255
2010 MSC: 17A32, 17A60
https://nasplib.isofts.kiev.ua/handle/123456789/188439
The first step in the study of all types of algebras is the description of such algebras having small dimensions. The structure of 3-dimensional Leibniz algebras is more complicated than 1 and 2-dimensional cases. In this paper, we consider the structure of Leibniz algebras of dimension 3 over the finite fields. In some cases, the structure of the algebra essentially depends on the characteristic of the field, in others on the solvability of specific equations in the field, and so on.
The author would like to express her sincere thanks to her scientific advisor Professor L. A. Kurdachenko.
en
Інститут прикладної математики і механіки НАН України
Algebra and Discrete Mathematics
On some Leibniz algebras, having small dimension
Article
published earlier
spellingShingle On some Leibniz algebras, having small dimension
Yashchuk, V.S.
title On some Leibniz algebras, having small dimension
title_full On some Leibniz algebras, having small dimension
title_fullStr On some Leibniz algebras, having small dimension
title_full_unstemmed On some Leibniz algebras, having small dimension
title_short On some Leibniz algebras, having small dimension
title_sort on some leibniz algebras, having small dimension
url https://nasplib.isofts.kiev.ua/handle/123456789/188439
work_keys_str_mv AT yashchukvs onsomeleibnizalgebrashavingsmalldimension