Nuprl Lemma : fst-orderedpairset
∀a,b:coSet{i:l}.  seteq(fst((a,b));a)
Proof
Definitions occuring in Statement : 
orderedpair-fst: fst(pr)
, 
orderedpairset: (a,b)
, 
seteq: seteq(s1;s2)
, 
coSet: coSet{i:l}
, 
all: ∀x:A. B[x]
Definitions unfolded in proof : 
rev_implies: P 
⇐ Q
, 
and: P ∧ Q
, 
iff: P 
⇐⇒ Q
, 
implies: P 
⇒ Q
, 
uall: ∀[x:A]. B[x]
, 
member: t ∈ T
, 
orderedpair-fst: fst(pr)
, 
all: ∀x:A. B[x]
Lemmas referenced : 
seteq_weakening, 
orderedpair-first, 
singleitem_functionality, 
seteq_functionality, 
singleitem-singleset, 
singleset_wf, 
orderedpairset_wf, 
orderedpair-fsts_wf, 
singleitem_wf, 
coSet_wf
Rules used in proof : 
productElimination, 
independent_functionElimination, 
dependent_functionElimination, 
because_Cache, 
hypothesisEquality, 
thin, 
isectElimination, 
sqequalHypSubstitution, 
hypothesis, 
extract_by_obid, 
introduction, 
cut, 
lambdaFormation, 
sqequalReflexivity, 
computationStep, 
sqequalTransitivity, 
sqequalSubstitution
Latex:
\mforall{}a,b:coSet\{i:l\}.    seteq(fst((a,b));a)
Date html generated:
2018_07_29-AM-10_02_10
Last ObjectModification:
2018_07_18-PM-03_04_59
Theory : constructive!set!theory
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