RUS  ENG
Full version
JOURNALS // Fundamentalnaya i Prikladnaya Matematika // Archive

Fundam. Prikl. Mat., 2016 Volume 21, Issue 6, Pages 93–113 (Mi fpm1770)

Refinement of Novikov–Betti numbers and of Novikov homology provided by an angle valued map

D. Burghelea

Department of Mathematics, The Ohio State University, Columbus, OH 43210, USA

Abstract: To a pair $(X,f)$, $X$ compact ANR and $f\colon X\to \mathbb S^1$ a continuous angle valued map, $\kappa$ a field, and a nonnegative integer $r$, one assigns a finite configuration of complex numbers $z$ with multiplicities $\delta^f_r(z)$ and a finite configuration of free $\kappa[t^{-1}, t]$-modules $\hat \delta^f_r$ of rank $\delta^ f_r(z)$ indexed by the same numbers $z$. This is in analogy with the configuration of eigenvalues and of generalized eigenspaces of a linear operator in a finite-dimensional complex vector space. The configuration $\delta^f_r$ refines the Novikov–Betti number in dimension $r$ and the configuration $\hat \delta^f_r$ refines the Novikov homology in dimension $r$ associated with the cohomology class defined by $f$. In the case of the field $\kappa= \mathbb C$, the configuration $\hat \delta^f_r$ provides by “von-Neumann completion” of a configuration $\hat{\hat \delta}^f_r$ of mutually orthogonal closed Hilbert submodules of the $L_2$-homology of the infinite cyclic cover of $X$ determined by the map $f$, which is an $L^\infty(\mathbb S^1)$-Hilbert module.

UDC: 515.142


 English version:
Journal of Mathematical Sciences (New York), 2020, 248:6, 728–742


© Steklov Math. Inst. of RAS, 2025