The present objectives of the Drive Uniformity Program at the University of Rochester are (a) to determine the radiation and drive uniformity requirementsfordirectly driven targets, and(b)toachieve the required degree of uniformity with multiple beam irradiation of spherical targets using overlapping beams. This integrated program, which began almost two years ago, has made steady progress in m...

We deene the counting classes #NC 1 , GapNC 1 , PNC 1 and C = NC 1. We prove that boolean circuits, algebraic circuits, programs over non-deterministic nite automata, and programs over constant integer matrices yield equivalent deenitions of the latter three classes. We investigate closure properties. We observe that #NC 1 #L, that PNC 1 L, and that C = NC 1 L. Then we exploit our nite automato...

A γ-quasi-clique in a simple undirected graph is a set of vertices which induces a subgraph with the edge density of at least γ for 0 < γ < 1. A cover of a graph by γ-quasi-cliques is a set of γ-quasi-cliques where each edge of the graph is contained in at least one quasi-clique. The minimum cover by γ-quasi-cliques problem asks for a γ-quasi-clique cover with the minimum number of quasi-clique...

The concept of the rock cycle and the “indefinite” length of geologic time were outlined first by James Hutton before he had ever seen an unconformity. Hutton drew general support of his theory from existing observations of unconformities from accounts in French, which he re-interpreted in light of his own ideas. Hutton then found his own field examples to test his ideas before coming upon Sicc...