79 research outputs found
K theory of smooth complete toric varieties and related spaces
The K-rings of non-singular complex pro jective varieties as well as quasi-
toric manifolds were described in terms of generators and relations in an
earlier work of the author with V. Uma. In this paper we obtain a similar
description for complete non-singular toric varieties. Indeed, our approach
enables us to obtain such a description for the more general class of torus
manifolds with locally standard torus action and orbit space a homology
polytope.Comment: 11 pages, no figure
On homeomorphisms and quasi-isometries of the real line
We show that the group of all pl-homeomorphisms of the reals having bounded
slopes surjects on the group of all quasi-isometries of . We prove that the following groups can be imbedded in : The
group of compactly supported pl-homeomorphisms of the reals, the Richard
Thompson group F, and the free group of rank the continuum.Comment: 9 page
On generalized Dold manifolds
Let be a smooth manifold with a (smooth) involution such
that . We call the space where a generalized Dold manifold. When
is an almost complex manifold and the differential is
conjugate complex linear on each fibre, we obtain a formula for the
Stiefel-Whitney polynomial of when . We obtain
results on stable parallelizability of and a very general criterion
for the (non) vanishing of the unoriented cobordism class in terms
of the corresponding properties for . These results are applied to the case
when is a complex flag manifold.Comment: 19 pages. A minor error in Prop. 2.5(iii) had been corrected. There
was a gap in the proof of Theorem 1.2 which has been corrected. Other minor
typos were correcte
Open String Diagrams I: Topological Type
An arbitrary Feynman graph for string field theory interactions is analysed
and the homeomorphism type of the corresponding world sheet surface is
completely determined even in the non-orientable cases. Algorithms are found to
mechanically compute the topological characteristics of the resulting surface
from the structure of the signed oriented graph. Whitney's
permutation-theoretic coding of graphs is utilized
Bounded automorphisms and quasi-isometries of finitely generated groups
Let G be any finitely generated infinite group. Denote by K(G) the FC-centre
of G, i.e., the subgroup of all elements of G whose centralizers are of finite
index in G. Let QI(G) denote the group of quasi-isometries of G with respect to
word metric. We observe that the natural homomorphism from the group of
automorphisms of G to QI(G) is a monomorphism only if K(G) equals the centre
Z(G) of G. The converse holds if K(G)=Z(G) is torsion free. We apply this
criterion to many interesting classes of groups.Comment: This is the corrected version. Published in J. Group Theory, 8
(2005), 515--52
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