Characterizations of Simply-connected Finite Polyhedra in 3-space
نویسنده
چکیده
(i) Y is simply-connected (ii) The first (integral) homology group of Y is trivial (iii) The first (integral) Betti number of Y is zero (iv) The first (integral) cohomology group of Y is trivial (v) The Euler Characteristic of Y is equal to the number of components of S\ Y (vi) Y has one (and hence all six) of the Phragmen-Brouwer properties [6] (The Phragmen-Brouwer properties are listed in the Appendix.)
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