05C99 7 13A15 3 zero-divisor graph 3 05C07 2 05C25 2 edge imbalance 2 essential graph 2 graph irregularity 2 graphic sequence 2 reduced ring 2 05C15 1 13A99 1 13F10 1 Hamming distance 1 adjacency matrix 1 annihilator graph 1 chromatic number 1 commutative ring 1 genus 1 ideal-based zero-divisor graph 1 local rings 1 planar 1 string 1