Nuprl Lemma : bag-member-map3
∀[T,U:Type].  ∀x:U. ∀bs:bag(T). ∀f:{v:T| v ↓∈ bs}  ⟶ U.  uiff(x ↓∈ bag-map(f;bs);↓∃v:T. (v ↓∈ bs ∧ (x = (f v) ∈ U)))
Proof
Definitions occuring in Statement : 
bag-member: x ↓∈ bs
, 
bag-map: bag-map(f;bs)
, 
bag: bag(T)
, 
uiff: uiff(P;Q)
, 
uall: ∀[x:A]. B[x]
, 
all: ∀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]
, 
all: ∀x:A. B[x]
, 
member: t ∈ T
, 
prop: ℙ
, 
uiff: uiff(P;Q)
, 
and: P ∧ Q
, 
uimplies: b supposing a
, 
squash: ↓T
, 
exists: ∃x:A. B[x]
, 
cand: A c∧ B
, 
so_lambda: λ2x.t[x]
, 
so_apply: x[s]
, 
iff: P 
⇐⇒ Q
, 
rev_implies: P 
⇐ Q
, 
implies: P 
⇒ Q
, 
bag-member: x ↓∈ bs
Lemmas referenced : 
bag-member_wf, 
bag-map-member-wf, 
bag-member-map, 
bag-subtype, 
equal_wf, 
squash_wf, 
exists_wf, 
bag-subtype2, 
iff_weakening_uiff, 
bag_wf
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
isect_memberFormation_alt, 
lambdaFormation_alt, 
cut, 
introduction, 
extract_by_obid, 
sqequalHypSubstitution, 
isectElimination, 
thin, 
hypothesisEquality, 
because_Cache, 
hypothesis, 
setEquality, 
dependent_functionElimination, 
equalityTransitivity, 
equalitySymmetry, 
independent_pairFormation, 
imageElimination, 
productElimination, 
setElimination, 
rename, 
dependent_pairFormation, 
productEquality, 
applyEquality, 
dependent_set_memberEquality, 
sqequalRule, 
imageMemberEquality, 
baseClosed, 
universeIsType, 
lambdaEquality, 
independent_functionElimination, 
independent_isectElimination, 
functionIsType, 
setIsType, 
inhabitedIsType, 
universeEquality
Latex:
\mforall{}[T,U:Type].
    \mforall{}x:U.  \mforall{}bs:bag(T).  \mforall{}f:\{v:T|  v  \mdownarrow{}\mmember{}  bs\}    {}\mrightarrow{}  U.    uiff(x  \mdownarrow{}\mmember{}  bag-map(f;bs);\mdownarrow{}\mexists{}v:T.  (v  \mdownarrow{}\mmember{}  bs  \mwedge{}  (x  =  (f  v)))\000C)
Date html generated:
2019_10_15-AM-11_02_23
Last ObjectModification:
2018_09_27-AM-11_19_30
Theory : bags
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