Nuprl Lemma : setmemfunc_wf
∀[x1,s1,x2,s2:coSet{i:l}].  (setmemfunc(x1; s1; x2; s2) ∈ seteq(x1;x2) ⇒ seteq(s1;s2) ⇒ {(x1 ∈ s1) ⇐⇒ (x2 ∈ s2)})
Proof
Definitions occuring in Statement : 
setmemfunc: setmemfunc(x1; s1; x2; s2), 
setmem: (x ∈ s), 
seteq: seteq(s1;s2), 
coSet: coSet{i:l}, 
uall: ∀[x:A]. B[x], 
guard: {T}, 
iff: P ⇐⇒ Q, 
implies: P ⇒ Q, 
member: t ∈ T
Definitions unfolded in proof : 
and: P ∧ Q, 
rev_implies: P ⇐ Q, 
iff: P ⇐⇒ Q, 
so_apply: x[s], 
guard: {T}, 
implies: P ⇒ Q, 
prop: ℙ, 
so_lambda: λ2x.t[x], 
all: ∀x:A. B[x], 
subtype_rel: A ⊆r B, 
setmemfunclemma_ext, 
setmemfunc: setmemfunc(x1; s1; x2; s2), 
member: t ∈ T, 
uall: ∀[x:A]. B[x]
Lemmas referenced : 
setmem_wf, 
iff_wf, 
seteq_wf, 
all_wf, 
coSet_wf, 
subtype_rel_self, 
setmemfunclemma_ext
Rules used in proof : 
because_Cache, 
isect_memberEquality, 
equalitySymmetry, 
equalityTransitivity, 
axiomEquality, 
hypothesisEquality, 
cumulativity, 
lambdaEquality, 
functionEquality, 
isectElimination, 
sqequalHypSubstitution, 
hypothesis, 
extract_by_obid, 
instantiate, 
thin, 
applyEquality, 
sqequalRule, 
cut, 
introduction, 
isect_memberFormation, 
sqequalReflexivity, 
computationStep, 
sqequalTransitivity, 
sqequalSubstitution
Latex:
\mforall{}[x1,s1,x2,s2:coSet\{i:l\}].
    (setmemfunc(x1;  s1;  x2;  s2)  \mmember{}  seteq(x1;x2)  {}\mRightarrow{}  seteq(s1;s2)  {}\mRightarrow{}  \{(x1  \mmember{}  s1)  \mLeftarrow{}{}\mRightarrow{}  (x2  \mmember{}  s2)\})
Date html generated:
2018_07_29-AM-09_51_36
Last ObjectModification:
2018_07_11-PM-00_35_12
Theory : constructive!set!theory
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