Nuprl Lemma : equiv_int_terms_functionality
∀[x1,x2,y1,y2:int_term()].  (uiff(x1 ≡ y1;x2 ≡ y2)) supposing (y1 ≡ y2 and x1 ≡ x2)
Proof
Definitions occuring in Statement : 
equiv_int_terms: t1 ≡ t2, 
int_term: int_term(), 
uiff: uiff(P;Q), 
uimplies: b supposing a, 
uall: ∀[x:A]. B[x]
Definitions unfolded in proof : 
uall: ∀[x:A]. B[x], 
member: t ∈ T, 
uimplies: b supposing a, 
uiff: uiff(P;Q), 
and: P ∧ Q, 
equiv_int_terms: t1 ≡ t2, 
all: ∀x:A. B[x], 
prop: ℙ, 
squash: ↓T, 
true: True, 
subtype_rel: A ⊆r B, 
guard: {T}, 
iff: P ⇐⇒ Q, 
rev_implies: P ⇐ Q, 
implies: P ⇒ Q
Lemmas referenced : 
equiv_int_terms_wf, 
int_term_wf, 
equal_wf, 
squash_wf, 
true_wf, 
int_term_value_wf, 
iff_weakening_equal
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
isect_memberFormation, 
introduction, 
cut, 
independent_pairFormation, 
sqequalHypSubstitution, 
lambdaFormation, 
hypothesis, 
functionEquality, 
intEquality, 
sqequalRule, 
lambdaEquality, 
dependent_functionElimination, 
thin, 
hypothesisEquality, 
axiomEquality, 
extract_by_obid, 
isectElimination, 
productElimination, 
independent_pairEquality, 
isect_memberEquality, 
because_Cache, 
equalityTransitivity, 
equalitySymmetry, 
applyEquality, 
imageElimination, 
universeEquality, 
functionExtensionality, 
natural_numberEquality, 
imageMemberEquality, 
baseClosed, 
independent_isectElimination, 
independent_functionElimination
Latex:
\mforall{}[x1,x2,y1,y2:int\_term()].    (uiff(x1  \mequiv{}  y1;x2  \mequiv{}  y2))  supposing  (y1  \mequiv{}  y2  and  x1  \mequiv{}  x2)
Date html generated:
2017_04_14-AM-08_57_35
Last ObjectModification:
2017_02_27-PM-03_40_56
Theory : omega
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