Nuprl Lemma : iff_functionality_wrt_iff
∀[P1,P2,Q1,Q2:ℙ].  ((P1 
⇐⇒ P2) 
⇒ (Q1 
⇐⇒ Q2) 
⇒ (P1 
⇐⇒ Q1 
⇐⇒ P2 
⇐⇒ Q2))
Proof
Definitions occuring in Statement : 
uall: ∀[x:A]. B[x]
, 
prop: ℙ
, 
iff: P 
⇐⇒ Q
, 
implies: P 
⇒ Q
Definitions unfolded in proof : 
uall: ∀[x:A]. B[x]
, 
implies: P 
⇒ Q
, 
iff: P 
⇐⇒ Q
, 
and: P ∧ Q
, 
member: t ∈ T
, 
prop: ℙ
, 
rev_implies: P 
⇐ Q
Lemmas referenced : 
iff_wf
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
Error :isect_memberFormation_alt, 
lambdaFormation, 
sqequalHypSubstitution, 
productElimination, 
thin, 
independent_pairFormation, 
hypothesisEquality, 
cut, 
introduction, 
extract_by_obid, 
isectElimination, 
hypothesis, 
independent_functionElimination, 
Error :inhabitedIsType, 
Error :universeIsType, 
universeEquality
Latex:
\mforall{}[P1,P2,Q1,Q2:\mBbbP{}].    ((P1  \mLeftarrow{}{}\mRightarrow{}  P2)  {}\mRightarrow{}  (Q1  \mLeftarrow{}{}\mRightarrow{}  Q2)  {}\mRightarrow{}  (P1  \mLeftarrow{}{}\mRightarrow{}  Q1  \mLeftarrow{}{}\mRightarrow{}  P2  \mLeftarrow{}{}\mRightarrow{}  Q2))
Date html generated:
2019_06_20-AM-11_16_59
Last ObjectModification:
2018_09_26-AM-10_24_33
Theory : core_2
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