Database
CLASSICAL FIRST-ORDER LOGIC WITH EQUALITY
Propositional calculus
Logical conjunction
biimpac
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biimparc
Metamath Proof Explorer
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Theorem
biimpac
Description:
Importation inference from a logical equivalence.
(Contributed by
NM
, 3-May-1994)
Ref
Expression
Hypothesis
biimpa.1
⊢
φ
→
ψ
↔
χ
Assertion
biimpac
⊢
ψ
∧
φ
→
χ
Proof
Step
Hyp
Ref
Expression
1
biimpa.1
⊢
φ
→
ψ
↔
χ
2
1
biimpcd
⊢
ψ
→
φ
→
χ
3
2
imp
⊢
ψ
∧
φ
→
χ