This paper is concerned with counting permutations which do not contain certain subsequences. The number of even and odd such permutations is found and the involutions among them are counted.â€¦ (More)

We present several problems involving geometric probability. Each is related to the division of a simplex or cube by a family of hyperplanes. Both the classical Eulerian numbers and their analogueâ€¦ (More)

We show that two determinants arising in di2erent mathematical contexts, both exhibiting striking factorization properties, are in fact related. These are the determinants of the matrix of chromaticâ€¦ (More)

The use of background investigation data in personnel screening is reviewed. Background investigations are routinely conducted on persons seeking positions of trust in law enforcement, the nuclearâ€¦ (More)

DEFINITION 2. A subset D of A(n, k) is called a line if ] DJ = k and if in some order the elements of D, written as column vectors, form an n X k matrix each row of which is constant, i.e., (a,â€¦ (More)