Nuprl Lemma : setmem_functionality
∀x1,s1,x2,s2:coSet{i:l}.  (seteq(x1;x2) ⇒ seteq(s1;s2) ⇒ {(x1 ∈ s1) ⇐⇒ (x2 ∈ s2)})
Proof
Definitions occuring in Statement : 
setmem: (x ∈ s), 
seteq: seteq(s1;s2), 
coSet: coSet{i:l}, 
guard: {T}, 
all: ∀x:A. B[x], 
iff: P ⇐⇒ Q, 
implies: P ⇒ Q
Definitions unfolded in proof : 
uall: ∀[x:A]. B[x], 
member: t ∈ T, 
all: ∀x:A. B[x]
Lemmas referenced : 
coSet_wf, 
setmemfunc_wf
Rules used in proof : 
because_Cache, 
hypothesis, 
hypothesisEquality, 
thin, 
isectElimination, 
sqequalHypSubstitution, 
extract_by_obid, 
cut, 
introduction, 
lambdaFormation, 
sqequalReflexivity, 
computationStep, 
sqequalTransitivity, 
sqequalSubstitution
Latex:
\mforall{}x1,s1,x2,s2:coSet\{i:l\}.    (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_38
Last ObjectModification:
2018_07_11-PM-00_36_00
Theory : constructive!set!theory
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