Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Semi-invertible extensions and asymptotic homomorphisms   We consider the semigroup $Ext(A,B)$ of extensions of a separable C*-algebra
$A$ by a stable C*-algebra $B$ modulo unitary equivalence and modulo
asymptotically split extensions. This semigroup contains the group
$Ext^{-1/2}(A,B)$ of invertible elements (i.e. of semi-invertible extensions).
We show that the functor $Ext^{1/2}(A,B)$ is homotopy invariant and that it
coincides with the functor of homotopy classes of asymptotic homomorphisms from
$C(\mathbb T)\otimes A$ to $M(B)$ that map $SA\subseteq C(\mathbb T)\otimes A$
into $B$.

18
The categories of this paper are: econ
25
The categories of this paper are: patt-sol
4
The categories of this paper are: cond-mat
1
The categories of this paper are: cs
8
The categories of this paper are: hep-ex
0
The categories of this paper are: hep-ph
13
The categories of this paper are: quant-ph
27
The categories of this paper are: comp-gas
12
The categories of this paper are: nucl-th
23
The categories of this paper are: solv-int
3
The categories of this paper are: physics
11
The categories of this paper are: hep-lat
32
The categories of this paper are: atom-ph
24
The categories of this paper are: dg-ga
35
The categories of this paper are: mtrl-th
36
The categories of this paper are: cmp-lg