Realizability algebras: a program to well order R

The theory of classical realizability is a framework in which we can develop the proof-program correspondence. Using this framework, we show how to transform into programs the proofs in classical analysis with dependent choice and the existence of a well ordering of the real line. The principal tools are: The notion of realizability algebra, which is a three-sorted variant of the well known combinatory algebra of Curry. An adaptation of the method of forcing used in set theory to prove consistency results. Here, it is used in another way, to obtain programs associated with a well ordering of R and the existence of a non trivial ultrafilter on N

On open 3-manifolds proper homotopy equivalent to geometrically-simply connected polyhedra

We prove that an open 3-manifold proper homotopy equivalent to a geometrically simply connected polyhedron is simply connected at infinity, generalizing a theorem of V.Poenaru.Comment: revised version, 11 pages, Topology Appl. (to appear

A Procedure for Sampling Nymphs of Saratoga Spittlebug, \u3ci\u3eAphrophora Saratogensis\u3c/i\u3e (Homoptera: Cercopidae), Using Percentage of Sample-Units Infested

A method is proposed for rapidly estimating the nymphal population of the Saratoga spittlebug on alternate host plants in young red pine plantations. The method is based on an assumption that the number of nymphs per sample unit is distributed within an infested plantation according to the negative binomial distribution. This method can be 1.1-11.0 times more efficient depending upon the density of plants and the nymphal population level