Database
CLASSICAL FIRST-ORDER LOGIC WITH EQUALITY
Propositional calculus
Logical conjunction
baibd
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rbaibd
Metamath Proof Explorer
Ascii
Unicode
Theorem
baibd
Description:
Move conjunction outside of biconditional.
(Contributed by
Mario Carneiro
, 11-Sep-2015)
Ref
Expression
Hypothesis
baibd.1
⊢
φ
→
ψ
↔
χ
∧
θ
Assertion
baibd
⊢
φ
∧
χ
→
ψ
↔
θ
Proof
Step
Hyp
Ref
Expression
1
baibd.1
⊢
φ
→
ψ
↔
χ
∧
θ
2
ibar
⊢
χ
→
θ
↔
χ
∧
θ
3
2
bicomd
⊢
χ
→
χ
∧
θ
↔
θ
4
1
3
sylan9bb
⊢
φ
∧
χ
→
ψ
↔
θ