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Yin Wei

Publications and source records attributed to Yin Wei.

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Weighted Homology and Cohomology of Weighted Polyhedra

We define the notion of weighted polyhedron which can be thought of as the geometric realization of a weighted simplicial complex introduced by Dawson. Moreover, we will define a weighted version of singular homology theory for a weighted polyhedron and prove that it is isomorphic to the weighted simplicial homology of the weighted polyhedron. This implies that weighted simplicial homology is an invariant under isomorphisms and more generally under certain type of homotopy equivalences of weighted polyhedra. Moreover, we will generalize the cup product and cap product to weighted singular cohomology. In addition, we will interpret some known theories of orbifolds in terms of our weighted singular homology and cohomology.

math.AT

Weighted homology theory of orbifolds and Weighted Polyhedra

We introduce two new homology theories of orbifolds from some special type of triangulations adapted to an orbifold, called AW-homology and DW-homology. The main idea in the definitions of these two homology theories is that we use divisibly weighted simplices as the building blocks of an orbifold and encode the orders of the local groups of the orbifold in the boundary maps of their chain complexes so that these two theories can reflect some structural information of the singular set of the orbifold. We prove that AW-homology and DW-homology groups are invariants of compact orbifolds under orbifold isomorphisms and more generally under certain type of homotopy equivalences of orbifolds. Moreover, we find that there exists a natural graded commutative product in the cohomology groups corresponding to the DW-homology, which generalizes the cup product in the ordinary simplicial cohomology. In addition, we introduce a broader class of objects called weighted polyhedra and develop our AW-homology and DW-homology theory in this broader setting. When a weighted polyhedron is based on a compact orientable homology n-manifold, we prove that its AW-homology and DW-homology satisfy a generalized version of Poincar\'e duality with respect to its DW-cohomology and AW-cohomology, respectively. Our goal is to generalize the whole simplicial (co)homology theory to any triangulable topological space with a suitable weight function.

math.AT