A given nonincreasing sequence D = (d1, d2, · · · , dn) is said to contain a (nonincreasing) repetition sequence D * = (di 1 , di 2 , · · · , di k) for some k ≤ n − 2 if all values of D − D * are distinct and for any di l ∈ D * there exists some dt ∈ D − D * such that di l = dt. For any pair of integers n and k with n ≥ k + 2, we investigate the existence… (More)
Consider the following two-person game on a graph G. Players I and II move alternatively to color a yet uncolored vertex of G properly using a pre-specified set of colors. Furthermore , Player II can only use the colors that have been used , unless he is forced to use a new color to guarantee that the graph is colored properly. The game ends when some… (More)
For any natural number k, a graph G is said to be pancyclic mod k if it contains a cycle of every length modulo k. In this paper, we show that every K 1,4-free graph G with minimum degree δ(G) ≥ k + 3 is pancyclic mod k and every claw-free graph G with δ(G) ≥ k + 1 is pancyclic mod k, which confirms Thomassen's conjecture  for claw-free graphs.
A result of Ladas; Lakshmikantham, and Papadakis  concerning oscillation caused by lag in linear first order retarded argument differential equations is generalized to the sublinear case. Examples showing that such generalization to the superlinear case is impossible are given. 0. Introduction. It is known (, for example) that (A) g e C(R, R), g(t) <… (More)
For two integers k(> 0) and s(≥ 0), a cycle of length l is called an (s mod k)-cycle if l ≡ s mod k. In this paper, the following conjecture of Chen, Dean, and Shreve  is proved: Every 2-connected graph with at least six vertices and minimum degree at least three contains a (2 mod 4)-cycle. 1 INTRODUCTION We use  for our notation and terminology. Our… (More)
In this paper, we investigate the sufficient conditions for a graph to contain a cycle (path) C such that G − V (C) is a disjoint union of cliques. In particular, sufficient conditions involving degree sum and neighborhood union are obtained.