Nuprl Lemma : f-singleton-subset
∀[A:Type]. ∀[eq:EqDecider(A)]. ∀[a:A]. ∀[x:fset(A)].  uiff({a} ⊆ x;a ∈ x)
Proof
Definitions occuring in Statement : 
fset-singleton: {x}
, 
f-subset: xs ⊆ ys
, 
fset-member: a ∈ s
, 
fset: fset(T)
, 
deq: EqDecider(T)
, 
uiff: uiff(P;Q)
, 
uall: ∀[x:A]. B[x]
, 
universe: Type
Definitions unfolded in proof : 
f-subset: xs ⊆ ys
, 
uiff: uiff(P;Q)
, 
and: P ∧ Q
, 
uimplies: b supposing a
, 
member: t ∈ T
, 
uall: ∀[x:A]. B[x]
, 
implies: P 
⇒ Q
, 
prop: ℙ
, 
so_lambda: λ2x.t[x]
, 
so_apply: x[s]
, 
all: ∀x:A. B[x]
, 
rev_implies: P 
⇐ Q
, 
iff: P 
⇐⇒ Q
, 
guard: {T}
Lemmas referenced : 
fset-member_witness, 
all_wf, 
isect_wf, 
equal_wf, 
fset-member_wf, 
and_wf, 
iff_weakening_uiff, 
fset-singleton_wf, 
member-fset-singleton, 
uiff_wf, 
f-subset_wf, 
fset_wf, 
deq_wf
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
cut, 
independent_pairFormation, 
isect_memberFormation, 
introduction, 
extract_by_obid, 
sqequalHypSubstitution, 
isectElimination, 
thin, 
because_Cache, 
hypothesisEquality, 
independent_functionElimination, 
hypothesis, 
cumulativity, 
sqequalRule, 
lambdaEquality, 
lambdaFormation, 
hyp_replacement, 
equalitySymmetry, 
dependent_set_memberEquality, 
applyLambdaEquality, 
setElimination, 
rename, 
productElimination, 
dependent_functionElimination, 
isect_memberEquality, 
equalityTransitivity, 
addLevel, 
independent_isectElimination, 
allFunctionality, 
universeEquality, 
independent_pairEquality
Latex:
\mforall{}[A:Type].  \mforall{}[eq:EqDecider(A)].  \mforall{}[a:A].  \mforall{}[x:fset(A)].    uiff(\{a\}  \msubseteq{}  x;a  \mmember{}  x)
Date html generated:
2017_04_17-AM-09_19_02
Last ObjectModification:
2017_02_27-PM-05_22_24
Theory : finite!sets
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