In this paper,we determine the Sombor index and some other vertex-degree-based topological indices for the nil-clean graphs of Z_(n),the ring of integers modulo n.
In 2006, Sanwong and Sullivan described the maximal congruences on the semigroup N consisting of all non-negative integers under standard multiplication, and on the semigroup T（X） consisting of all total transformat...In 2006, Sanwong and Sullivan described the maximal congruences on the semigroup N consisting of all non-negative integers under standard multiplication, and on the semigroup T（X） consisting of all total transformations of an infinite set X under composition. Here, we determine all maximal congruences on the semigroup Zn under multiplication modulo n. And, when Y lohtain in X, we do the same for the semigroup T（X, Y） consisting of all elements of T（X） whose range is contained in Y. We also characterise the minimal congruences on T（X. Y）.展开更多
基金supported by the National Natural Science Foundation of China(Nos.12261001,12461001)the Research Foundation Ability Enhancement Project for Young and Middle aged Teachers in Guangxi Universities(No.025KY0477)。
文摘In this paper,we determine the Sombor index and some other vertex-degree-based topological indices for the nil-clean graphs of Z_(n),the ring of integers modulo n.
文摘In 2006, Sanwong and Sullivan described the maximal congruences on the semigroup N consisting of all non-negative integers under standard multiplication, and on the semigroup T（X） consisting of all total transformations of an infinite set X under composition. Here, we determine all maximal congruences on the semigroup Zn under multiplication modulo n. And, when Y lohtain in X, we do the same for the semigroup T（X, Y） consisting of all elements of T（X） whose range is contained in Y. We also characterise the minimal congruences on T（X. Y）.
