Nuprl Lemma : fset-only_wf
∀[T:Type]. ∀[eq:EqDecider(T)]. ∀[P:T ⟶ 𝔹]. ∀[s:fset(T)].
  (only x ∈ s s.t. P[x] ∈ {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-only: only x ∈ s s.t. P[x]
, 
fset-member: a ∈ s
, 
fset: fset(T)
, 
deq: EqDecider(T)
, 
assert: ↑b
, 
bool: 𝔹
, 
uimplies: b supposing a
, 
uall: ∀[x:A]. B[x]
, 
so_apply: x[s]
, 
all: ∀x:A. B[x]
, 
not: ¬A
, 
implies: P 
⇒ Q
, 
and: P ∧ Q
, 
member: t ∈ T
, 
set: {x:A| B[x]} 
, 
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
, 
all: ∀x:A. B[x]
, 
implies: P 
⇒ Q
, 
prop: ℙ
, 
so_apply: x[s]
, 
so_lambda: λ2x.t[x]
, 
fset-only: only x ∈ s s.t. P[x]
, 
and: P ∧ Q
, 
exists: ∃x:A. B[x]
, 
false: False
, 
not: ¬A
, 
subtype_rel: A ⊆r B
, 
decidable: Dec(P)
, 
or: P ∨ Q
, 
iff: P 
⇐⇒ Q
, 
rev_implies: P 
⇐ Q
, 
cand: A c∧ B
, 
guard: {T}
, 
uiff: uiff(P;Q)
Lemmas referenced : 
istype-universe, 
fset-member_wf, 
assert_wf, 
not_wf, 
all_wf, 
fset_wf, 
bool_wf, 
deq_wf, 
decidable__equal_int, 
fset-size_wf, 
fset-filter_wf, 
fset-size-one, 
iff_weakening_uiff, 
member-fset-filter, 
fset-item_wf, 
fset-item-member, 
and_wf, 
exists_wf
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
Error :isect_memberFormation_alt, 
introduction, 
cut, 
sqequalHypSubstitution, 
hypothesis, 
sqequalRule, 
axiomEquality, 
equalityTransitivity, 
equalitySymmetry, 
Error :functionIsType, 
extract_by_obid, 
isectElimination, 
thin, 
hypothesisEquality, 
Error :inhabitedIsType, 
Error :universeIsType, 
applyEquality, 
Error :equalityIsType1, 
Error :isect_memberEquality_alt, 
Error :lambdaEquality_alt, 
functionEquality, 
because_Cache, 
universeEquality, 
lambdaEquality, 
voidElimination, 
lemma_by_obid, 
independent_pairFormation, 
dependent_pairFormation, 
independent_functionElimination, 
lambdaFormation, 
dependent_functionElimination, 
natural_numberEquality, 
unionElimination, 
Error :lambdaFormation_alt, 
Error :productIsType, 
productElimination, 
Error :dependent_pairFormation_alt, 
Error :isectIsType, 
productEquality, 
promote_hyp, 
independent_isectElimination, 
dependent_set_memberEquality
Latex:
\mforall{}[T:Type].  \mforall{}[eq:EqDecider(T)].  \mforall{}[P:T  {}\mrightarrow{}  \mBbbB{}].  \mforall{}[s:fset(T)].
    (only  x  \mmember{}  s  s.t.  P[x]  \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 
          (\mneg{}(\mforall{}x:T.  (x  \mmember{}  s  {}\mRightarrow{}  (\mneg{}\muparrow{}P[x])))))
Date html generated:
2019_06_20-PM-02_00_16
Last ObjectModification:
2018_10_06-AM-11_23_46
Theory : finite!sets
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