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SUPPLEMENTARY MATERIAL (USERS' MATHBOXES)
Mathbox for Richard Penner
Propositions from _Begriffsschrift_
_Begriffsschrift_ Chapter II with logical equivalence
axfrege58a
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ax-frege58a
Metamath Proof Explorer
Ascii
Structured
Theorem
axfrege58a
Description:
Identical to
anifp
. Justification for
ax-frege58a
.
(Contributed by
RP
, 28-Mar-2020)
Ref
Expression
Assertion
axfrege58a
⊢
( (
𝜓
∧
𝜒
) → if- (
𝜑
,
𝜓
,
𝜒
) )
Proof
Step
Hyp
Ref
Expression
1
anifp
⊢
( (
𝜓
∧
𝜒
) → if- (
𝜑
,
𝜓
,
𝜒
) )