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In this paper, we establish a lower bound on the number of inducing simple n-gons in grid-like arrangements of lines. We also show that the complexity associated with counting the number of inducing n-gons in an arrangement of collinear segments is #P-complete.

We investigate the complexity of membership problems for {∪,∩, ̄ , +,×}-circuits computing sets of integers. These problems are a natural modification of the membership problems for circuits computing sets of natural numbers studied by McKenzie and Wagner (2003). We show that there are several membership problems for which the complexity in the case of integers differs significantly from the ca...

In normal activities such as walking, rn­ning, kneeling, climbing stairs and gettmg in and out of chairs the loa pu OI.the human knee joint can exceed five times the weight of the body. Nowadays large num­bers of people make ! urtrer d mands on the knee in participatmg 1_n sucli sport  as football, tennis and long distance runnng. It is no wonder that many people go mto their later years with o...

The problem of counting unlabelled subtrees of a tree (that is, subtrees that are distinct up to isomorphism) is #P-complete, and hence equivalent in computational difficulty to evaluating the permanent of a 0,1-matrix.

Implications of a formal context (G,M, I) have a minimal implication basis, called Duquenne-Guigues basis or stem base. It is shown that the problem of deciding whether a set of attributes is a premise of the stem base is in coNP and determining the size of the stem base is polynomially Turing equivalent to a #P-complete problem.