Nuprl Lemma : eqff_to_assert
∀[b:𝔹]. uiff(b = ff;↑¬bb)
Proof
Definitions occuring in Statement : 
bnot: ¬bb
, 
assert: ↑b
, 
bfalse: ff
, 
bool: 𝔹
, 
uiff: uiff(P;Q)
, 
uall: ∀[x:A]. B[x]
, 
equal: s = t ∈ T
Definitions unfolded in proof : 
uall: ∀[x:A]. B[x]
, 
member: t ∈ T
, 
uiff: uiff(P;Q)
, 
and: P ∧ Q
, 
uimplies: b supposing a
, 
assert: ↑b
, 
ifthenelse: if b then t else f fi 
, 
all: ∀x:A. B[x]
, 
implies: P 
⇒ Q
, 
bool: 𝔹
, 
true: True
, 
prop: ℙ
, 
false: False
, 
sq_type: SQType(T)
, 
guard: {T}
, 
subtype_rel: A ⊆r B
, 
rev_implies: P 
⇐ Q
, 
iff: P 
⇐⇒ Q
Lemmas referenced : 
bnot_wf, 
bool_wf, 
true_wf, 
false_wf, 
equal_wf, 
equal-wf-T-base, 
assert_wf, 
subtype_base_sq, 
bool_subtype_base, 
bfalse_wf, 
iff_weakening_uiff, 
sqequal-wf-base, 
sqeqff_to_assert, 
uiff_wf
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
isect_memberFormation, 
introduction, 
cut, 
sqequalRule, 
sqequalHypSubstitution, 
productElimination, 
thin, 
independent_pairEquality, 
isect_memberEquality, 
isectElimination, 
hypothesisEquality, 
extract_by_obid, 
hypothesis, 
lambdaFormation, 
unionElimination, 
axiomEquality, 
equalityTransitivity, 
equalitySymmetry, 
voidElimination, 
dependent_functionElimination, 
independent_functionElimination, 
baseClosed, 
independent_pairFormation, 
instantiate, 
cumulativity, 
independent_isectElimination, 
sqequalAxiom, 
sqequalIntensionalEquality, 
applyEquality, 
addLevel, 
because_Cache
Latex:
\mforall{}[b:\mBbbB{}].  uiff(b  =  ff;\muparrow{}\mneg{}\msubb{}b)
Date html generated:
2017_04_14-AM-07_14_17
Last ObjectModification:
2017_02_27-PM-02_50_05
Theory : union
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