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Metamath Proof Explorer


Theorem orcd

Description: Deduction introducing a disjunct. A translation of natural deduction rule \/ IR ( \/ insertion right), see natded . (Contributed by NM, 20-Sep-2007)

Ref Expression
Hypothesis orcd.1 φ ψ
Assertion orcd φ ψ χ

Proof

Step Hyp Ref Expression
1 orcd.1 φ ψ
2 orc ψ ψ χ
3 1 2 syl φ ψ χ