Database
CLASSICAL FIRST-ORDER LOGIC WITH EQUALITY
Propositional calculus
Logical conjunction
biancomi
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biancomd
Metamath Proof Explorer
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Theorem
biancomi
Description:
Commuting conjunction in a biconditional.
(Contributed by
Peter Mazsa
, 17-Jun-2018)
Ref
Expression
Hypothesis
biancomi.1
⊢
φ
↔
χ
∧
ψ
Assertion
biancomi
⊢
φ
↔
ψ
∧
χ
Proof
Step
Hyp
Ref
Expression
1
biancomi.1
⊢
φ
↔
χ
∧
ψ
2
ancom
⊢
ψ
∧
χ
↔
χ
∧
ψ
3
1
2
bitr4i
⊢
φ
↔
ψ
∧
χ