Nuprl Lemma : sq_or_functionality_wrt_iff
∀[P1,P2,Q1,Q2:ℙ].  ({P1 ⇐⇒ P2} ⇒ {Q1 ⇐⇒ Q2} ⇒ {P1 ↓∨ Q1 ⇐⇒ P2 ↓∨ Q2})
Proof
Definitions occuring in Statement : 
sq_or: a ↓∨ b, 
uall: ∀[x:A]. B[x], 
prop: ℙ, 
guard: {T}, 
iff: P ⇐⇒ Q, 
implies: P ⇒ Q
Definitions unfolded in proof : 
guard: {T}, 
sq_or: a ↓∨ b, 
uall: ∀[x:A]. B[x], 
member: t ∈ T, 
implies: P ⇒ Q, 
iff: P ⇐⇒ Q, 
and: P ∧ Q, 
squash: ↓T, 
or: P ∨ Q, 
prop: ℙ, 
rev_implies: P ⇐ Q
Lemmas referenced : 
iff_wf, 
or_wf, 
squash_wf
Rules used in proof : 
sqequalSubstitution, 
sqequalRule, 
sqequalReflexivity, 
sqequalTransitivity, 
computationStep, 
isect_memberFormation, 
introduction, 
cut, 
lambdaFormation, 
sqequalHypSubstitution, 
productElimination, 
thin, 
independent_pairFormation, 
imageElimination, 
unionElimination, 
independent_functionElimination, 
hypothesis, 
inlFormation, 
hypothesisEquality, 
imageMemberEquality, 
baseClosed, 
inrFormation, 
lemma_by_obid, 
isectElimination, 
lambdaEquality, 
dependent_functionElimination, 
independent_pairEquality, 
universeEquality, 
isect_memberEquality, 
because_Cache
Latex:
\mforall{}[P1,P2,Q1,Q2:\mBbbP{}].    (\{P1  \mLeftarrow{}{}\mRightarrow{}  P2\}  {}\mRightarrow{}  \{Q1  \mLeftarrow{}{}\mRightarrow{}  Q2\}  {}\mRightarrow{}  \{P1  \mdownarrow{}\mvee{}  Q1  \mLeftarrow{}{}\mRightarrow{}  P2  \mdownarrow{}\mvee{}  Q2\})
Date html generated:
2016_05_13-PM-03_13_28
Last ObjectModification:
2016_01_06-PM-05_48_08
Theory : core_2
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