Nuprl Lemma : cons-has-member
∀[S:Type]. ∀a:S. ∀[b:S List]. ∃x:S. (x ∈ [a / b])
Proof
Definitions occuring in Statement : 
l_member: (x ∈ l), 
cons: [a / b], 
list: T List, 
uall: ∀[x:A]. B[x], 
all: ∀x:A. B[x], 
exists: ∃x:A. B[x], 
universe: Type
Definitions unfolded in proof : 
uall: ∀[x:A]. B[x], 
all: ∀x:A. B[x], 
exists: ∃x:A. B[x], 
member: t ∈ T, 
l_member: (x ∈ l), 
nat: ℕ, 
le: A ≤ B, 
and: P ∧ Q, 
less_than': less_than'(a;b), 
false: False, 
not: ¬A, 
implies: P ⇒ Q, 
top: Top, 
select: L[n], 
cons: [a / b], 
cand: A c∧ B, 
nat_plus: ℕ+, 
less_than: a < b, 
squash: ↓T, 
true: True, 
guard: {T}, 
uimplies: b supposing a, 
sq_stable: SqStable(P), 
prop: ℙ
Lemmas referenced : 
istype-false, 
istype-le, 
length_of_cons_lemma, 
istype-void, 
add_nat_plus, 
length_wf_nat, 
istype-less_than, 
cons_wf, 
length_wf, 
select_wf, 
sq_stable__le, 
l_member_wf, 
list_wf, 
istype-universe
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
Error :isect_memberFormation_alt, 
Error :lambdaFormation_alt, 
Error :dependent_pairFormation_alt, 
hypothesisEquality, 
Error :dependent_set_memberEquality_alt, 
natural_numberEquality, 
sqequalRule, 
independent_pairFormation, 
hypothesis, 
cut, 
introduction, 
extract_by_obid, 
sqequalHypSubstitution, 
isectElimination, 
thin, 
because_Cache, 
dependent_functionElimination, 
Error :isect_memberEquality_alt, 
voidElimination, 
imageMemberEquality, 
baseClosed, 
Error :inhabitedIsType, 
setElimination, 
rename, 
imageElimination, 
productElimination, 
Error :equalityIstype, 
equalityTransitivity, 
equalitySymmetry, 
independent_functionElimination, 
Error :productIsType, 
independent_isectElimination, 
Error :universeIsType, 
instantiate, 
universeEquality
Latex:
\mforall{}[S:Type].  \mforall{}a:S.  \mforall{}[b:S  List].  \mexists{}x:S.  (x  \mmember{}  [a  /  b])
Date html generated:
2019_06_20-PM-00_40_38
Last ObjectModification:
2019_03_06-AM-11_06_29
Theory : list_0
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