idempotent 8 20M20 7 05A10 4 05A15 4 full transformation 4 94B60 3 group algebra 3 quasi-idempotent 3 representation 3 13F99 2 16G10 2 16G20 2 16P40 2 16S34 2 16W10 2 20C05 2 20M 2 20M17 2 20M18 2 47L30 2 94B15 2 Bezout ring 2 Cayley table 2 Hilbert space 2 Peirce decomposition 2 anti-isomorphism 2 breadth 2 char-complete set 2 characteristic property 2 clean ring 2