Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Defect formation from defect--anti-defect annihilations   We show that when a topological defect with extended world-volume annihilates
with an anti-defect, there arise topological defects with dimensions less than
those of the original defects by one. Domain wall annihilations create vortices
while monopole-string annihilations result in instantons. We find that twisted
domain wall rings are vortices, whereas twisted monopole rings are instantons.

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The categories of this paper are: cs
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The categories of this paper are: solv-int
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The categories of this paper are: math-ph
31
The categories of this paper are: ao-sci
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The categories of this paper are: physics
16
The categories of this paper are: stat
20
The categories of this paper are: acc-phys
33
The categories of this paper are: plasm-ph
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The categories of this paper are: adap-org
35
The categories of this paper are: mtrl-th
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The categories of this paper are: dg-ga
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The categories of this paper are: econ
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The categories of this paper are: hep-ex
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The categories of this paper are: chao-dyn
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The categories of this paper are: bayes-an
34
The categories of this paper are: chem-ph