Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Enhanced Gauge Symmetries and K3 Surfaces   String-string duality dictates that type IIA strings compactified on a K3
surface acquire non-abelian gauge groups for certain values of the K3 moduli.
We argue that, contrary to expectation, the theories for which such enhanced
gauge symmetries appear are not orbifolds in the string sense. For a specific
example we show that a theory with enhanced gauge symmetry and an orbifold
theory have the same classical K3 surface as a target space but the value of
the ``B-field'' differs. This raises the possibility that the conformal field
theory associated to a string theory with an enhanced gauge group is badly
behaved in some way.

29
The categories of this paper are: funct-an
10
The categories of this paper are: q-bio
37
The categories of this paper are: supr-con
0
The categories of this paper are: hep-ph
36
The categories of this paper are: cmp-lg
28
The categories of this paper are: alg-geom
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The categories of this paper are: math-ph
11
The categories of this paper are: hep-lat
8
The categories of this paper are: hep-ex
24
The categories of this paper are: dg-ga
13
The categories of this paper are: quant-ph
35
The categories of this paper are: mtrl-th
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The categories of this paper are: solv-int
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The categories of this paper are: q-fin
6
The categories of this paper are: astro-ph
5
The categories of this paper are: gr-qc