Let G ≤ Sn be a permutation group of degree n with a quotient isomorphic to Ak. We show that if n < (1/2 − o(1))k then the extension splits. Motivated by this result, Guralnick and Liebeck have shown that the conclusion fails to hold if we allow n to be n = 2k(k − 1), establishing a tight quadratic growth rate for the smallest degree of a faithful permutation representation of a non-split exten...

The paper is devoted to a concept of aggregation of binary fuzzy relations. Consider two n-ary vectors, when we know the degrees to which corresponding components are in relation we can measure the degree to which vectors are in relation. Tasks with such background justify the necessity of aggregation of binary fuzzy relations and we contribute to the topic in this paper. First we recall the ap...

in this paper, we determine the degree distance of the complement of arbitrary mycielskian graphs. it is well known that almost all graphs have diameter two. we determine this graphical invariant for the mycielskian of graphs with diameter two.

let g_1 and g_2 be simple connected graphs with disjoint vertex sets v(g_1) and v(g_2), respectively. for given vertices a_1in v(g_1) and a_2in v(g_2), a splice of g_1 and g_2 by vertices a_1 and a_2 is defined by identifying the vertices a_1 and a_2 in the :union: of g_1 and g_2. in this paper, we present exact formulas for computing some vertex-degree-based graph invariants of splice of graphs.

Random networks are widely used to model complex networks and research their properties. In order to get a good approximation of complex networks encountered in various disciplines of science, the ability to tune various statistical properties of random networks is very important. In this Brief Report we present an algorithm which is able to construct arbitrarily degree-degree correlated networ...

We rely on the books of Boutet de Monvel and Guillemin [4], Blackadar [2] and of Beals and Greiner [1] (see also the book of Taylor ([7]). The properties of the Heisenberg algebra will be discussed more fully in a forthcoming paper of G. Mendoza and the present authors. Let ΨHe(X) be the Heisenberg algebra, of ‘parabolic’ pseudodifferential operators associated to the contact structure on X. Th...

the degree kirchhoff index of a connected graph $g$ is defined as‎ ‎the sum of the terms $d_i,d_j,r_{ij}$ over all pairs of vertices‎, ‎where $d_i$ is the‎ ‎degree of the $i$-th vertex‎, ‎and $r_{ij}$ the resistance distance between the $i$-th and‎ ‎$j$-th vertex of $g$‎. ‎bounds for the degree kirchhoff index of the line and para-line‎ ‎graphs are determined‎. ‎the special case of regular grap...

The Turing degrees 3d were introduced by Kleene and Post ([9], 1954) to isolate and study those properties of the subsets of the natural numbers N which are expressed purely in terms of relative computability. Intuitively, we form 3d by identifying any pair of subsets of N which are mutually computable and ordering the resulting equivalence classes by relative computability. The natural hierarc...