Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: K-Theory of Approximately Central Projections in the Flip Orbifold   For an approximately central (AC) Powers-Rieffel projection $e$ in the
irrational Flip orbifold C*-algebra $A_\theta^\Phi,$ where $\Phi$ is the Flip
automorphism of the rotation C*-algebra $A_\theta,$ we compute the Connes-Chern
character of the cutdown of any projection by $e$ in terms of K-theoretic
invariants of these projections. This result is then applied to computing a
complete K-theoretic invariant for the projection $e$ with respect to central
equivalence (within the orbifold). Thus, in addition to the canonical trace,
there is a $4\times6$ K-matrix invariant $K(e)$ arising from unbounded traces
of the cutdowns of a canonically constructed basis for $K_0(A_\theta^\Phi) =
\mathbb Z^6$. Thanks to a theorem of Kishimoto, this enables us to tell when AC
projections in $A_\theta^\Phi$ are Murray-von Neumann equivalent via an
approximately central partial isometry (or unitary) in $A_\theta^\Phi$. As
additional application, we obtain the K-matrix of canonical SL$(2,\mathbb
Z)$-automorphisms of $e$ and show that there is a subsequence of $e$ such that
$e, \sigma(e), \kappa(e), \kappa^2(e), \sigma\kappa(e), \sigma\kappa^2(e)$ --
which are the orbit elements of $e$ under the symmetric group $S_3 \subset$
SL$(2,\mathbb Z)$ -- are pairwise centrally not equivalent, and that each
SL$(2,\mathbb Z)$ image of $e$ is centrally equivalent to one of these, where
$\sigma, \kappa$ are the Fourier and Cubic transform automorphisms of the
rotation algebra.

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The categories of this paper are: supr-con
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The categories of this paper are: physics
0
The categories of this paper are: hep-ph
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The categories of this paper are: acc-phys
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The categories of this paper are: adap-org
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The categories of this paper are: chao-dyn
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The categories of this paper are: bayes-an
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The categories of this paper are: hep-ex
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The categories of this paper are: econ
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The categories of this paper are: nucl-th
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The categories of this paper are: patt-sol
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The categories of this paper are: solv-int
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The categories of this paper are: funct-an
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The categories of this paper are: cmp-lg
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The categories of this paper are: plasm-ph
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The categories of this paper are: atom-ph