Nuprl Lemma : dl-equiv_wf
∀[phi,psi:Prop].  ((phi 
⇐⇒ psi) ∈ ℙ')
Proof
Definitions occuring in Statement : 
dl-equiv: (phi 
⇐⇒ psi)
, 
dl-prop: Prop
, 
uall: ∀[x:A]. B[x]
, 
prop: ℙ
, 
member: t ∈ T
Definitions unfolded in proof : 
uall: ∀[x:A]. B[x]
, 
member: t ∈ T
, 
dl-equiv: (phi 
⇐⇒ psi)
, 
prop: ℙ
, 
and: P ∧ Q
Lemmas referenced : 
dl-valid_wf, 
dl-implies_wf, 
dl-prop_wf
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
isect_memberFormation_alt, 
introduction, 
cut, 
sqequalRule, 
productEquality, 
extract_by_obid, 
sqequalHypSubstitution, 
isectElimination, 
thin, 
hypothesisEquality, 
hypothesis, 
axiomEquality, 
equalityTransitivity, 
equalitySymmetry, 
inhabitedIsType, 
isect_memberEquality_alt, 
isectIsTypeImplies, 
universeIsType
Latex:
\mforall{}[phi,psi:Prop].    ((phi  \mLeftarrow{}{}\mRightarrow{}  psi)  \mmember{}  \mBbbP{}')
Date html generated:
2019_10_15-AM-11_44_15
Last ObjectModification:
2019_03_27-AM-00_13_56
Theory : dynamic!logic
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