Database
CLASSICAL FIRST-ORDER LOGIC WITH EQUALITY
Propositional calculus
Logical conjunction
impcom
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con3dimp
Metamath Proof Explorer
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Theorem
impcom
Description:
Importation inference with commuted antecedents.
(Contributed by
NM
, 25-May-2005)
Ref
Expression
Hypothesis
imp.1
⊢
φ
→
ψ
→
χ
Assertion
impcom
⊢
ψ
∧
φ
→
χ
Proof
Step
Hyp
Ref
Expression
1
imp.1
⊢
φ
→
ψ
→
χ
2
1
com12
⊢
ψ
→
φ
→
χ
3
2
imp
⊢
ψ
∧
φ
→
χ