Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Intuitionistic Existential Instantiation and Epsilon Symbol   A natural deduction system for intuitionistic predicate logic with
existential \ instantiation rule presented here uses Hilbert's $\e$-symbol. It
is conservative over intuitionistic predicate logic. We provide a completeness
proof for a suitable Kripke semantics, sketch an approach to a normalization
proof, survey related work and state some open problems. Our system extends
intuitionistic systems with $\e$-symbol due to A. Dragalin and Sh. Maehara.

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The categories of this paper are: adap-org
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The categories of this paper are: atom-ph
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The categories of this paper are: eess
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The categories of this paper are: dg-ga
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The categories of this paper are: physics
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The categories of this paper are: hep-ex
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The categories of this paper are: nucl-th
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The categories of this paper are: funct-an
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The categories of this paper are: solv-int
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The categories of this paper are: nucl-ex
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The categories of this paper are: acc-phys
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The categories of this paper are: patt-sol
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The categories of this paper are: gr-qc
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The categories of this paper are: nlin
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The categories of this paper are: mtrl-th
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The categories of this paper are: q-bio