Algebraic classification of linking pairings on 3-manifolds
Algebraic classification of linking pairings on 3-manifolds
复制标题
3-流形上连接配对的代数分类
DOI:
10.1007/bf01457818
复制
发表时间:
1980
影响因子:
1.4
通讯作者:
Sadayoshi Kojima
中科院分区:
文献类型:
--
作者:
A. Kawauchi;Sadayoshi Kojima
A linking is understood as a pair (G, ~b) such that G is a finite abelian group and ~b is a nonsingular, symmetric bilinear pairing G x G~Q/Z. It is convenient to identify a linking (G, ~) with a matrix which represents ~b relative to the generators of a cyclic splitting of G unless confusion might occur. The linking occurs often in the study of topology. For example, given a closed oriented 3-manifold M, we have a unique linking (~HI(M),q~M) defined by the Poincar~ duality, where "rHI(M ) is the torsion part of the integral homology group Hi(M). The purpose of this paper is to determine completely the structure of the abelian semigroup 9l of all linkings (up to isomorphism) under block sum and to observe that any linking is isomorphic to the linking ~b~ of a closed connected oriented 3-manifold M. To do this, we shall present a complete system of invariants of isomorphic linkings, which arises naturally from our purpose. Such a complete system had already been known by Seifert [ 11] in the case of odd-primary groups, and in general by Burger [2, Satz 5] in terms of Minkowski's beautiful theory. Though they are related directly or indirectly to each other (cf. Fox [5]), we do not discuss here any relation between them.