Nuprl Lemma : setmem-setunionfun
∀s:coSet{i:l}. ∀f:{x:coSet{i:l}| (x ∈ s)}  ⟶ coSet{i:l}.
  (set-function{i:l}(s; x.f[x]) 
⇒ (∀y:coSet{i:l}. ((y ∈  ⋃x∈s.f[x]) 
⇐⇒ ∃x:coSet{i:l}. ((x ∈ s) ∧ (y ∈ f[x])))))
Proof
Definitions occuring in Statement : 
setunionfun:  ⋃x∈s.f[x]
, 
set-function: set-function{i:l}(s; x.f[x])
, 
setmem: (x ∈ s)
, 
coSet: coSet{i:l}
, 
so_apply: x[s]
, 
all: ∀x:A. B[x]
, 
exists: ∃x:A. B[x]
, 
iff: P 
⇐⇒ Q
, 
implies: P 
⇒ Q
, 
and: P ∧ Q
, 
set: {x:A| B[x]} 
, 
function: x:A ⟶ B[x]
Definitions unfolded in proof : 
setunionfun:  ⋃x∈s.f[x]
, 
guard: {T}
, 
pi2: snd(t)
, 
pi1: fst(t)
, 
set-dom: set-dom(s)
, 
set-item: set-item(s;x)
, 
set-function: set-function{i:l}(s; x.f[x])
, 
top: Top
, 
exists: ∃x:A. B[x]
, 
mk-coset: mk-coset(T;f)
, 
rev_implies: P 
⇐ Q
, 
so_apply: x[s]
, 
so_lambda: λ2x.t[x]
, 
uall: ∀[x:A]. B[x]
, 
prop: ℙ
, 
subtype_rel: A ⊆r B
, 
member: t ∈ T
, 
and: P ∧ Q
, 
iff: P 
⇐⇒ Q
, 
implies: P 
⇒ Q
, 
all: ∀x:A. B[x]
Lemmas referenced : 
set-item_wf, 
set-dom_wf, 
seteq_inversion, 
seteq_weakening, 
setmem_functionality, 
seteq_wf, 
setmem-iff, 
setmem-coset, 
setmem_functionality_1, 
setmem-mk-coset, 
mk-coset_wf, 
setmem-unionfun-implies, 
set-function_wf, 
exists_wf, 
coSet_wf, 
setunionfun_wf, 
setmem_wf, 
coSet_subtype, 
subtype_coSet
Rules used in proof : 
dependent_pairEquality, 
dependent_pairFormation, 
universeEquality, 
functionExtensionality, 
because_Cache, 
voidEquality, 
voidElimination, 
isect_memberEquality, 
independent_functionElimination, 
dependent_functionElimination, 
functionEquality, 
dependent_set_memberEquality, 
productEquality, 
instantiate, 
cumulativity, 
setEquality, 
lambdaEquality, 
isectElimination, 
rename, 
thin, 
productElimination, 
sqequalRule, 
sqequalHypSubstitution, 
applyEquality, 
hypothesisEquality, 
hypothesis, 
extract_by_obid, 
introduction, 
cut, 
hypothesis_subsumption, 
independent_pairFormation, 
lambdaFormation, 
sqequalReflexivity, 
computationStep, 
sqequalTransitivity, 
sqequalSubstitution
Latex:
\mforall{}s:coSet\{i:l\}.  \mforall{}f:\{x:coSet\{i:l\}|  (x  \mmember{}  s)\}    {}\mrightarrow{}  coSet\{i:l\}.
    (set-function\{i:l\}(s;  x.f[x])
    {}\mRightarrow{}  (\mforall{}y:coSet\{i:l\}.  ((y  \mmember{}    \mcup{}x\mmember{}s.f[x])  \mLeftarrow{}{}\mRightarrow{}  \mexists{}x:coSet\{i:l\}.  ((x  \mmember{}  s)  \mwedge{}  (y  \mmember{}  f[x])))))
Date html generated:
2018_07_29-AM-09_52_54
Last ObjectModification:
2018_07_18-PM-02_44_57
Theory : constructive!set!theory
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