Nuprl Lemma : member-fset-mapfilter
∀[T:Type]. ∀[eqT:EqDecider(T)]. ∀[P:T ⟶ 𝔹]. ∀[X:Type]. ∀[eqX:EqDecider(X)]. ∀[f:{x:T| ↑(P x)}  ⟶ X]. ∀[s:fset(T)].
∀[x:X].
  uiff(x ∈ fset-mapfilter(f;P;s);↓∃y:T. (y ∈ s ∧ (↑(P y)) ∧ (x = (f y) ∈ X)))
Proof
Definitions occuring in Statement : 
fset-mapfilter: fset-mapfilter(f;P;s), 
fset-member: a ∈ s, 
fset: fset(T), 
deq: EqDecider(T), 
assert: ↑b, 
bool: 𝔹, 
uiff: uiff(P;Q), 
uall: ∀[x:A]. B[x], 
exists: ∃x:A. B[x], 
squash: ↓T, 
and: P ∧ Q, 
set: {x:A| B[x]} , 
apply: f a, 
function: x:A ⟶ B[x], 
universe: Type, 
equal: s = t ∈ T
Definitions unfolded in proof : 
uall: ∀[x:A]. B[x], 
member: t ∈ T, 
uiff: uiff(P;Q), 
and: P ∧ Q, 
uimplies: b supposing a, 
squash: ↓T, 
prop: ℙ, 
implies: P ⇒ Q, 
exists: ∃x:A. B[x], 
quotient: x,y:A//B[x; y], 
so_apply: x[s], 
so_lambda: λ2x.t[x], 
fset: fset(T), 
cand: A c∧ B, 
subtype_rel: A ⊆r B, 
iff: P ⇐⇒ Q, 
all: ∀x:A. B[x], 
fset-member: a ∈ s, 
fset-mapfilter: fset-mapfilter(f;P;s), 
rev_implies: P ⇐ Q, 
decidable: Dec(P), 
or: P ∨ Q, 
sq_type: SQType(T), 
guard: {T}, 
true: True, 
false: False, 
not: ¬A, 
istype: istype(T)
Lemmas referenced : 
fset-member_wf, 
fset-mapfilter_wf, 
fset-member_witness, 
squash_wf, 
assert_wf, 
equal_wf, 
istype-assert, 
fset_wf, 
deq_wf, 
bool_wf, 
istype-universe, 
set-equal_wf, 
list_wf, 
equal-wf-base, 
exists_wf, 
set_wf, 
subtype_rel_self, 
l_member_wf, 
subtype_rel_dep_function, 
member-mapfilter, 
mapfilter_wf, 
assert-deq-member, 
list_subtype_fset, 
decidable__fset-member, 
subtype_base_sq, 
int_subtype_base, 
set-equal-reflex
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
Error :isect_memberFormation_alt, 
introduction, 
cut, 
independent_pairFormation, 
hypothesis, 
sqequalHypSubstitution, 
imageElimination, 
sqequalRule, 
imageMemberEquality, 
hypothesisEquality, 
thin, 
baseClosed, 
Error :universeIsType, 
extract_by_obid, 
isectElimination, 
independent_functionElimination, 
productEquality, 
applyEquality, 
Error :dependent_set_memberEquality_alt, 
productElimination, 
independent_pairEquality, 
Error :isect_memberEquality_alt, 
Error :isectIsTypeImplies, 
Error :inhabitedIsType, 
because_Cache, 
Error :functionIsType, 
Error :setIsType, 
instantiate, 
universeEquality, 
pertypeElimination, 
dependent_set_memberEquality, 
setEquality, 
functionExtensionality, 
lambdaEquality, 
cumulativity, 
pointwiseFunctionalityForEquality, 
lambdaFormation, 
rename, 
setElimination, 
independent_isectElimination, 
equalitySymmetry, 
equalityTransitivity, 
dependent_functionElimination, 
dependent_pairFormation, 
unionElimination, 
intEquality, 
natural_numberEquality, 
voidElimination, 
promote_hyp, 
Error :lambdaFormation_alt, 
pointwiseFunctionality, 
Error :lambdaEquality_alt, 
Error :productIsType, 
Error :equalityIsType4, 
Error :dependent_pairFormation_alt, 
Error :equalityIstype
Latex:
\mforall{}[T:Type].  \mforall{}[eqT:EqDecider(T)].  \mforall{}[P:T  {}\mrightarrow{}  \mBbbB{}].  \mforall{}[X:Type].  \mforall{}[eqX:EqDecider(X)].
\mforall{}[f:\{x:T|  \muparrow{}(P  x)\}    {}\mrightarrow{}  X].  \mforall{}[s:fset(T)].  \mforall{}[x:X].
    uiff(x  \mmember{}  fset-mapfilter(f;P;s);\mdownarrow{}\mexists{}y:T.  (y  \mmember{}  s  \mwedge{}  (\muparrow{}(P  y))  \mwedge{}  (x  =  (f  y))))
Date html generated:
2019_06_20-PM-01_58_50
Last ObjectModification:
2018_11_23-PM-02_42_36
Theory : finite!sets
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