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Mathbox for Richard Penner
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Additional work on conditional logical operator
ifpid2
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ifpim2
Metamath Proof Explorer
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Theorem
ifpid2
Description:
Restate wff as conditional logic operator.
(Contributed by
RP
, 20-Apr-2020)
Ref
Expression
Assertion
ifpid2
⊢
φ
↔
if-
φ
⊤
⊥
Proof
Step
Hyp
Ref
Expression
1
tru
⊢
⊤
2
1
olci
⊢
¬
φ
∨
⊤
3
2
biantrur
⊢
φ
∨
⊥
↔
¬
φ
∨
⊤
∧
φ
∨
⊥
4
fal
⊢
¬
⊥
5
4
biorfi
⊢
φ
↔
φ
∨
⊥
6
dfifp4
⊢
if-
φ
⊤
⊥
↔
¬
φ
∨
⊤
∧
φ
∨
⊥
7
3
5
6
3bitr4i
⊢
φ
↔
if-
φ
⊤
⊥