Nuprl Lemma : member-f-union-aux
∀[T,A:Type].
  ∀eqt:EqDecider(T). ∀eqa:EqDecider(A). ∀g:T ⟶ fset(A). ∀L:T List. ∀a:A.
    (a ∈ f-union(eqt;eqa;L;x.g[x]) ⇐⇒ (∃x∈L. a ∈ g[x]))
Proof
Definitions occuring in Statement : 
f-union: f-union(domeq;rngeq;s;x.g[x]), 
fset-member: a ∈ s, 
fset: fset(T), 
l_exists: (∃x∈L. P[x]), 
list: T List, 
deq: EqDecider(T), 
uall: ∀[x:A]. B[x], 
so_apply: x[s], 
all: ∀x:A. B[x], 
iff: P ⇐⇒ Q, 
function: x:A ⟶ B[x], 
universe: Type
Definitions unfolded in proof : 
uall: ∀[x:A]. B[x], 
all: ∀x:A. B[x], 
f-union: f-union(domeq;rngeq;s;x.g[x]), 
member: t ∈ T, 
so_lambda: λ2x.t[x], 
so_lambda: λ2x y.t[x; y], 
so_apply: x[s], 
so_apply: x[s1;s2], 
prop: ℙ, 
implies: P ⇒ Q, 
top: Top, 
iff: P ⇐⇒ Q, 
and: P ∧ Q, 
guard: {T}, 
or: P ∨ Q, 
subtype_rel: A ⊆r B, 
rev_implies: P ⇐ Q, 
false: False, 
not: ¬A, 
fset-member: a ∈ s, 
assert: ↑b, 
ifthenelse: if b then t else f fi , 
deq-member: x ∈b L, 
reduce: reduce(f;k;as), 
list_ind: list_ind, 
nil: [], 
it: ⋅, 
bfalse: ff, 
fset: fset(T), 
uimplies: b supposing a
Lemmas referenced : 
list_wf, 
fset_wf, 
deq_wf, 
list_induction, 
all_wf, 
iff_wf, 
fset-member_wf, 
list_accum_wf, 
fset-union_wf, 
or_wf, 
l_exists_wf, 
l_member_wf, 
list_accum_nil_lemma, 
list_accum_cons_lemma, 
l_exists_wf_nil, 
fset-member_witness, 
l_exists_nil, 
l_exists_cons, 
cons_wf, 
member-fset-union, 
set-equal_wf, 
set-equal-equiv, 
nil_wf, 
set-equal-reflex, 
quotient-member-eq
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
isect_memberFormation, 
lambdaFormation, 
hypothesisEquality, 
cut, 
lemma_by_obid, 
sqequalHypSubstitution, 
isectElimination, 
thin, 
hypothesis, 
functionEquality, 
universeEquality, 
sqequalRule, 
lambdaEquality, 
cumulativity, 
because_Cache, 
applyEquality, 
setElimination, 
rename, 
setEquality, 
independent_functionElimination, 
dependent_functionElimination, 
isect_memberEquality, 
voidElimination, 
voidEquality, 
independent_pairFormation, 
inrFormation, 
introduction, 
unionElimination, 
productElimination, 
addLevel, 
allFunctionality, 
impliesFunctionality, 
orFunctionality, 
inlFormation, 
independent_isectElimination, 
equalityTransitivity, 
equalitySymmetry
Latex:
\mforall{}[T,A:Type].
    \mforall{}eqt:EqDecider(T).  \mforall{}eqa:EqDecider(A).  \mforall{}g:T  {}\mrightarrow{}  fset(A).  \mforall{}L:T  List.  \mforall{}a:A.
        (a  \mmember{}  f-union(eqt;eqa;L;x.g[x])  \mLeftarrow{}{}\mRightarrow{}  (\mexists{}x\mmember{}L.  a  \mmember{}  g[x]))
Date html generated:
2016_05_14-PM-03_39_10
Last ObjectModification:
2015_12_26-PM-06_42_23
Theory : finite!sets
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