We define the notions of strong and strict recurrency for actions countable ordered groups on σ-finite non atomic measure spaces with quasi-invariant measures. show that is equivalent to existence weakly wandering sets positive measure. also certain p.m.p ergodic system not strictly recurrent, which shows are equivalent.

OBJECTIVE Early recurrency after surgery for acute endocarditis is a life-threatening complication. Allograft valves are supposed to have a higher resistance to recurrent infection, thus several authors claim them to be the replacement device of choice in cases of aortic endocarditis. However, allografts have two major drawbacks: their availability is limited, and most of the patients require r...

We show that amenability of a group acting by homeomorphisms can be deduced from a certain local property of the action and recurrency of the orbital Schreier graphs. This applies to a wide class of groups, amenability of which was an open problem, as well as unifies many known examples to one general proof. In particular, this includes Grigorchuk’s group, Basilica group, groups associated with...

We inv estigate the applicability of an adaptive neural network to problems with time-dependent input by demonstrating that a deterministic parser for natural language inputs of significant syntactic complexity can be developed using recurrent connectionist architectures. The traditional stacking mechanism, known to be necessary for proper treatment of context-free languages in symbolic systems...

The objective of control generation in logic programming is to derive a computation rule for a program that is efficient and yet does not compromise program correctness. Progress in solving this fundamental problem in logic programming has been slow and, to date, only partial solutions have been proposed. Previously proposed schemes are either inefficient, incomplete (incorrect) or difficult to...