Nuprl Lemma : member-fset-map
∀[T:Type]. ∀[eqT:EqDecider(T)]. ∀[X:Type]. ∀[eqX:EqDecider(X)]. ∀[f:T ⟶ X]. ∀[s:fset(T)]. ∀[x:X].
  uiff(x ∈ fset-map(f;s);↓∃y:T. (y ∈ s ∧ (x = (f y) ∈ X)))
Proof
Definitions occuring in Statement : 
fset-map: fset-map(f;s)
, 
fset-member: a ∈ s
, 
fset: fset(T)
, 
deq: EqDecider(T)
, 
uiff: uiff(P;Q)
, 
uall: ∀[x:A]. B[x]
, 
exists: ∃x:A. B[x]
, 
squash: ↓T
, 
and: P ∧ Q
, 
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]
, 
fset: fset(T)
, 
quotient: x,y:A//B[x; y]
, 
fset-map: fset-map(f;s)
, 
fset-member: a ∈ s
, 
all: ∀x:A. B[x]
, 
iff: P 
⇐⇒ Q
, 
cand: A c∧ B
, 
rev_implies: P 
⇐ Q
, 
subtype_rel: A ⊆r B
, 
guard: {T}
, 
decidable: Dec(P)
, 
or: P ∨ Q
, 
not: ¬A
, 
false: False
, 
sq_type: SQType(T)
, 
true: True
Lemmas referenced : 
fset-member_wf, 
fset-map_wf, 
fset-member_witness, 
squash_wf, 
equal_wf, 
fset_wf, 
deq_wf, 
istype-universe, 
assert-deq-member, 
map_wf, 
member-map, 
subtype_rel_self, 
list_wf, 
set-equal_wf, 
decidable__fset-member, 
set-equal-reflex, 
l_member_wf, 
subtype_base_sq, 
int_subtype_base
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, 
productElimination, 
independent_pairEquality, 
Error :isect_memberEquality_alt, 
Error :isectIsTypeImplies, 
Error :inhabitedIsType, 
because_Cache, 
Error :functionIsType, 
instantiate, 
universeEquality, 
pointwiseFunctionalityForEquality, 
pertypeElimination, 
dependent_functionElimination, 
equalityTransitivity, 
equalitySymmetry, 
Error :dependent_pairFormation_alt, 
Error :productIsType, 
Error :equalityIstype, 
sqequalBase, 
unionElimination, 
promote_hyp, 
Error :lambdaFormation_alt, 
pointwiseFunctionality, 
voidElimination, 
Error :equalityIsType4, 
intEquality, 
natural_numberEquality, 
cumulativity, 
independent_isectElimination
Latex:
\mforall{}[T:Type].  \mforall{}[eqT:EqDecider(T)].  \mforall{}[X:Type].  \mforall{}[eqX:EqDecider(X)].  \mforall{}[f:T  {}\mrightarrow{}  X].  \mforall{}[s:fset(T)].  \mforall{}[x:X].
    uiff(x  \mmember{}  fset-map(f;s);\mdownarrow{}\mexists{}y:T.  (y  \mmember{}  s  \mwedge{}  (x  =  (f  y))))
Date html generated:
2019_06_20-PM-01_58_53
Last ObjectModification:
2018_11_23-PM-04_42_10
Theory : finite!sets
Home
Index