Nuprl Lemma : fset-find_wf
∀[T:Type]. ∀[eq:EqDecider(T)]. ∀[P:T ⟶ 𝔹]. ∀[s:fset(T)].
  (fset-find(P;s) ∈ {x:T| x ∈ s ∧ (↑(P x))} ) supposing 
     ((∀x,y:T.  (x ∈ s ⇒ y ∈ s ⇒ (↑(P x)) ⇒ (↑(P y)) ⇒ (x = y ∈ T))) and 
     (↓∃x:T. (x ∈ s ∧ (↑(P x)))))
Proof
Definitions occuring in Statement : 
fset-find: fset-find(P;s), 
fset-member: a ∈ s, 
fset: fset(T), 
deq: EqDecider(T), 
assert: ↑b, 
bool: 𝔹, 
uimplies: b supposing a, 
uall: ∀[x:A]. B[x], 
all: ∀x:A. B[x], 
exists: ∃x:A. B[x], 
squash: ↓T, 
implies: P ⇒ Q, 
and: P ∧ Q, 
member: t ∈ T, 
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, 
uimplies: b supposing a, 
squash: ↓T, 
prop: ℙ, 
so_lambda: λ2x.t[x], 
implies: P ⇒ Q, 
so_apply: x[s], 
and: P ∧ Q, 
fset: fset(T), 
quotient: x,y:A//B[x; y], 
fset-find: fset-find(P;s), 
so_lambda: λ2x y.t[x; y], 
so_apply: x[s1;s2], 
all: ∀x:A. B[x], 
true: True, 
subtype_rel: A ⊆r B, 
guard: {T}, 
iff: P ⇐⇒ Q, 
exists: ∃x:A. B[x], 
fset-member: a ∈ s, 
rev_implies: P ⇐ Q, 
ge: i ≥ j , 
decidable: Dec(P), 
or: P ∨ Q, 
less_than: a < b, 
satisfiable_int_formula: satisfiable_int_formula(fmla), 
false: False, 
not: ¬A, 
top: Top, 
set-equal: set-equal(T;x;y), 
cand: A c∧ B
Lemmas referenced : 
all_wf, 
fset-member_wf, 
assert_wf, 
equal_wf, 
squash_wf, 
exists_wf, 
fset_wf, 
bool_wf, 
deq_wf, 
equal-wf-base, 
list_wf, 
set-equal_wf, 
quotient-member-eq, 
set-equal-equiv, 
true_wf, 
iff_weakening_equal, 
assert-deq-member, 
l_member_wf, 
deq-member_wf, 
filter_type, 
subtype_rel_dep_function, 
subtype_rel_self, 
set_wf, 
list-subtype, 
hd_wf, 
length-filter-pos, 
l_exists_iff, 
decidable__le, 
length_wf, 
satisfiable-full-omega-tt, 
intformand_wf, 
intformnot_wf, 
intformle_wf, 
itermConstant_wf, 
itermVar_wf, 
intformless_wf, 
int_formula_prop_and_lemma, 
int_formula_prop_not_lemma, 
int_formula_prop_le_lemma, 
int_term_value_constant_lemma, 
int_term_value_var_lemma, 
int_formula_prop_less_lemma, 
int_formula_prop_wf, 
subtype_rel_sets
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
isect_memberFormation, 
introduction, 
cut, 
sqequalHypSubstitution, 
imageElimination, 
hypothesis, 
sqequalRule, 
axiomEquality, 
equalityTransitivity, 
equalitySymmetry, 
extract_by_obid, 
isectElimination, 
thin, 
cumulativity, 
hypothesisEquality, 
lambdaEquality, 
functionEquality, 
applyEquality, 
functionExtensionality, 
isect_memberEquality, 
because_Cache, 
productEquality, 
universeEquality, 
pointwiseFunctionalityForEquality, 
setEquality, 
pertypeElimination, 
productElimination, 
independent_isectElimination, 
dependent_functionElimination, 
independent_functionElimination, 
addLevel, 
existsFunctionality, 
independent_pairFormation, 
natural_numberEquality, 
imageMemberEquality, 
baseClosed, 
promote_hyp, 
allFunctionality, 
lambdaFormation, 
andLevelFunctionality, 
setElimination, 
rename, 
dependent_set_memberEquality, 
unionElimination, 
dependent_pairFormation, 
int_eqEquality, 
intEquality, 
voidElimination, 
voidEquality, 
computeAll, 
applyLambdaEquality
Latex:
\mforall{}[T:Type].  \mforall{}[eq:EqDecider(T)].  \mforall{}[P:T  {}\mrightarrow{}  \mBbbB{}].  \mforall{}[s:fset(T)].
    (fset-find(P;s)  \mmember{}  \{x:T|  x  \mmember{}  s  \mwedge{}  (\muparrow{}(P  x))\}  )  supposing 
          ((\mforall{}x,y:T.    (x  \mmember{}  s  {}\mRightarrow{}  y  \mmember{}  s  {}\mRightarrow{}  (\muparrow{}(P  x))  {}\mRightarrow{}  (\muparrow{}(P  y))  {}\mRightarrow{}  (x  =  y)))  and 
          (\mdownarrow{}\mexists{}x:T.  (x  \mmember{}  s  \mwedge{}  (\muparrow{}(P  x)))))
Date html generated:
2017_02_20-AM-10_49_10
Last ObjectModification:
2017_02_02-PM-05_25_18
Theory : finite!sets
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