Nuprl Lemma : fset-union-closed
∀[T:Type]. ∀[eq:EqDecider(T)]. ∀[fs:(T ⟶ T) List]. ∀[as,bs:fset(T)].
  ((as ⋃ bs closed under fs)) supposing ((bs closed under fs) and (as closed under fs))
Proof
Definitions occuring in Statement : 
fset-closed: (s closed under fs)
, 
fset-union: x ⋃ y
, 
fset: fset(T)
, 
list: T List
, 
deq: EqDecider(T)
, 
uimplies: b supposing a
, 
uall: ∀[x:A]. B[x]
, 
function: x:A ⟶ B[x]
, 
universe: Type
Definitions unfolded in proof : 
fset-closed: (s closed under fs)
, 
uall: ∀[x:A]. B[x]
, 
member: t ∈ T
, 
uimplies: b supposing a
, 
all: ∀x:A. B[x]
, 
so_lambda: λ2x.t[x]
, 
prop: ℙ
, 
so_apply: x[s]
, 
iff: P 
⇐⇒ Q
, 
and: P ∧ Q
, 
implies: P 
⇒ Q
, 
rev_implies: P 
⇐ Q
, 
l_all: (∀x∈L.P[x])
, 
int_seg: {i..j-}
, 
guard: {T}
, 
lelt: i ≤ j < k
, 
decidable: Dec(P)
, 
or: P ∨ Q
, 
satisfiable_int_formula: satisfiable_int_formula(fmla)
, 
exists: ∃x:A. B[x]
, 
false: False
, 
not: ¬A
, 
top: Top
, 
less_than: a < b
, 
squash: ↓T
Lemmas referenced : 
member-fset-union, 
deq_wf, 
list_wf, 
fset_wf, 
l_all_wf, 
int_seg_wf, 
int_formula_prop_less_lemma, 
intformless_wf, 
decidable__lt, 
int_formula_prop_wf, 
int_term_value_var_lemma, 
int_term_value_constant_lemma, 
int_formula_prop_le_lemma, 
int_formula_prop_not_lemma, 
int_formula_prop_and_lemma, 
itermVar_wf, 
itermConstant_wf, 
intformle_wf, 
intformnot_wf, 
intformand_wf, 
satisfiable-full-omega-tt, 
decidable__le, 
length_wf, 
int_seg_properties, 
select_wf, 
fset-member_witness, 
fset-union_wf, 
l_member_wf, 
fset-member_wf, 
isect_wf, 
all_wf, 
l_all_iff
Rules used in proof : 
sqequalSubstitution, 
sqequalRule, 
sqequalReflexivity, 
sqequalTransitivity, 
computationStep, 
isect_memberFormation, 
introduction, 
cut, 
lemma_by_obid, 
sqequalHypSubstitution, 
isectElimination, 
thin, 
functionEquality, 
hypothesisEquality, 
dependent_functionElimination, 
lambdaEquality, 
hypothesis, 
applyEquality, 
setElimination, 
rename, 
setEquality, 
productElimination, 
independent_functionElimination, 
lambdaFormation, 
because_Cache, 
isect_memberEquality, 
cumulativity, 
independent_isectElimination, 
natural_numberEquality, 
unionElimination, 
dependent_pairFormation, 
int_eqEquality, 
intEquality, 
voidElimination, 
voidEquality, 
independent_pairFormation, 
computeAll, 
imageElimination, 
equalityTransitivity, 
equalitySymmetry, 
universeEquality, 
inlFormation, 
inrFormation
Latex:
\mforall{}[T:Type].  \mforall{}[eq:EqDecider(T)].  \mforall{}[fs:(T  {}\mrightarrow{}  T)  List].  \mforall{}[as,bs:fset(T)].
    ((as  \mcup{}  bs  closed  under  fs))  supposing  ((bs  closed  under  fs)  and  (as  closed  under  fs))
Date html generated:
2016_05_14-PM-03_44_48
Last ObjectModification:
2016_01_14-PM-10_39_59
Theory : finite!sets
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