نتایج جستجو برای: first betti number

تعداد نتایج: 2400077  

Journal: :Annali di Matematica Pura ed Applicata (1923 -) 2020

Journal: :Advances in Mathematics 2021

We construct a compact formal 7-manifold with closed $G_2$-structure and first Betti number $b_1=1$, which does not admit any torsion-free $G_2$-structure, that is, it such the holonomy group of associated metric is subgroup $G_2$. also associative calibrated (hence volume-minimizing) 3-tori respect to this and, for each those 3-tori, we show 3-dimensional family non-trivial deformations. fibra...

2012
MIKHAIL ERSHOV

Let G be a finitely generated group and G = G0 ⊇ G1 ⊇ G2 ⊇ · · · a descending chain of finite index normal subgroups of G. Given a field K, we consider the sequence b1(Gi;K) [G:Gi] of normalized first Betti numbers of Gi with coefficients in K, which we call a K-approximation for b (2) 1 (G), the first L2-Betti number of G. In this paper we address the questions of when Qapproximation and Fp-ap...

2005
JOSEPH MASTERS

We give examples of closed hyperbolic 3-manifolds with first Betti number 2 and 3 for which no sequence of finite abelian covering spaces increases the first Betti number. For 3-manifolds M with first Betti number 2 we give a characterization in terms of some generalized self-linking numbers of M , for there to exist a family of Zn covering spaces, Mn, in which β1(Mn) increases linearly with n....

2005
TIM D. COCHRAN JOSEPH MASTERS

We give examples of closed hyperbolic 3-manifolds with first Betti number 2 and 3 for which no sequence of finite abelian covering spaces increases the first Betti number. For 3-manifolds M with first Betti number 2 we give a characterization in terms of some generalized self-linking numbers of M , for there to exist a family of Zn covering spaces, Mn, in which β1(Mn) increases linearly with n....

نمودار تعداد نتایج جستجو در هر سال

با کلیک روی نمودار نتایج را به سال انتشار فیلتر کنید