THE LEFSCHETZ NUMBER OF AN n-VALUED MULTIMAP
THE LEFSCHETZ NUMBER OF AN n-VALUED MULTIMAP
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发表时间:
2007
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通讯作者:
RobertF Brown
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作者:
RobertF Brown
An n-valued multimap is a continuous multivalued function �: X ⊸ Y such that �(x) is an unordered subset of n points of Y for each x ∈ X. If X and Y are finite polyhedra, theninduces a graded homomorphism of homology with rational coefficients. For�: X ⊸ X the Lefschetz number L(�) ofis defined to be the Lefschetz number of the induced homomorphism. If L(�) 6 0, then every n-valued multimap homotopic tohas a fixed point. If X is the circle, then the Lefschetz number of � is related to the Nielsen number N(�) of Schirmer as in the single-valued case, that is, N(�) = |L(�)|. Subject Classificaton 55M20; 55N25 of homology groups with coefficients in a field, all of which he c sidered induced homomorphisms of φ. When φ is a single-valued continuous function, this vector space consists of the scalar mul- tiples of the usual induced homology homomorphism. If X is a finite polyhedron, so the homology with rational coefficientsH∗(X) is finite-dimensional, and h = {hk: Hk(X) → Hk(X)} is a graded homomorphism, then its Lefschetz number �(h) is defined by