Given a graph G and a natural number k, the k graph product of G = (V,E) is the graph with vertex set V . For every two vertices x = (x1, . . . , xk) and y = (y1, . . . , yk) in V , an edge is placed according to a predefined rule. Graph products are a basic combinatorial object, widely studied and used in different areas such as hardness of approximation, information theory, etc. We study grap...

Mass d i s t r i b u t i o n s of i o n i c atomic and molecular fragments s p u t t e r e d from carbon s u r f a c e s by s i n g l y charged p o s i t i v e c l u s t e r ions con ta in ing 80 water molecules have been determined. With c l u s t e r k i n e t i c energy of 240 keV s i g n i f i c a n t y i e l d s of molecular fragments con ta in ing up t o 2 1 carbon'atoms were observed. Io...