For arbitrary graphs G1 and G2, define the Ramsey number R(G1,G2) to be the minimum positive integer N such that in every bicoloring of edges of the complete graph KN with, say, red and blue colors, there is either a red copy of G1 or a blue copy of G2. The classical Ramsey number r(k, l) is in our terminology R(Kk,Kl). Call a family F of graphs linear Ramsey if there exists a constant C = C(F)...

A general upper bound for the size Ramsey number f(Ps , KI,t) matching the exact value for s ::; 7 and t sufficiently large is presented. Moreover, the remaining unknown values of the size Ramsey number for pairs of forests of order at most five are determined.

Let F , G and H be simple graphs. We say F → (G,H) if for every 2-coloring of the edges of F there exists a monochromatic G orH in F . The Ramsey number r(G,H) is defined as r(G,H) = min{|V (F )| : F → (G,H)}, while the restricted size Ramsey number r(G,H) is defined as r(G,H) = min{|E(F )| : F → (G,H), |V (F )| = r(G,H)}. In this paper we determine previously unknown restricted size Ramsey num...

The star-critical Ramsey number r∗(H1,H2) is the smallest integer k such that every red/blue coloring of the edges of Kn −K1,n−k−1 contains either a red copy of H1 or a blue copy of H2, where n is the graph Ramsey number R(H1,H2). We study the cases of r∗(C4, Cn) and R(C4,Wn). In particular, we prove that r∗(C4, Cn) = 5 for all n > 4, obtain a general characterization of Ramsey-critical (C4,Wn)...

Implications of field quantization on Ramsey interferometry are discussed and general conditions for the occurrence of interference are obtained. Interferences do not occur if the fields in two Ramsey zones have precise number of photons. However in this case we show how two atom (like two photon) interferometry can be used to discern a variety of interference effects as the two independent Ram...

A partial ordering P is chain-Ramsey if, for every natural number n and every coloring of the n-element chains from P in finitely many colors, there is a monochromatic subordering Q isomorphic to P. Chain-Ramsey partial orderings stratify naturally into levels. We show that a countably infinite partial ordering with finite levels is chain-Ramsey if and only if it is biembeddable with one of a c...