Nuprl Lemma : member-free-dl-meet
∀[X:Type]
  ∀as,bs:X List List. ∀x:X List.
    ((x ∈ free-dl-meet(as;bs)) 
⇐⇒ ∃u,v:X List. ((u ∈ as) ∧ (v ∈ bs) ∧ (x = (u @ v) ∈ (X List))))
Proof
Definitions occuring in Statement : 
free-dl-meet: free-dl-meet(as;bs)
, 
l_member: (x ∈ l)
, 
append: as @ bs
, 
list: T List
, 
uall: ∀[x:A]. B[x]
, 
all: ∀x:A. B[x]
, 
exists: ∃x:A. B[x]
, 
iff: P 
⇐⇒ Q
, 
and: P ∧ Q
, 
universe: Type
, 
equal: s = t ∈ T
Definitions unfolded in proof : 
uall: ∀[x:A]. B[x]
, 
free-dl-meet: free-dl-meet(as;bs)
, 
all: ∀x:A. B[x]
, 
iff: P 
⇐⇒ Q
, 
and: P ∧ Q
, 
implies: P 
⇒ Q
, 
or: P ∨ Q
, 
member: t ∈ T
, 
uimplies: b supposing a
, 
not: ¬A
, 
false: False
, 
prop: ℙ
, 
so_lambda: λ2x.t[x]
, 
so_apply: x[s]
, 
rev_implies: P 
⇐ Q
, 
guard: {T}
, 
so_lambda: λ2x y.t[x; y]
, 
so_apply: x[s1;s2]
, 
exists: ∃x:A. B[x]
, 
top: Top
, 
cand: A c∧ B
Lemmas referenced : 
null_nil_lemma, 
btrue_wf, 
member-implies-null-eq-bfalse, 
list_wf, 
nil_wf, 
btrue_neq_bfalse, 
or_wf, 
l_member_wf, 
exists_wf, 
equal_wf, 
append_wf, 
list_accum_wf, 
map_wf, 
all_wf, 
iff_wf, 
list_induction, 
list_accum_nil_lemma, 
list_accum_cons_lemma, 
cons_wf, 
member_wf, 
member_append, 
member_map, 
cons_member, 
and_wf
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
isect_memberFormation, 
sqequalRule, 
cut, 
lambdaFormation, 
independent_pairFormation, 
sqequalHypSubstitution, 
unionElimination, 
thin, 
introduction, 
extract_by_obid, 
hypothesis, 
isectElimination, 
cumulativity, 
hypothesisEquality, 
independent_isectElimination, 
equalityTransitivity, 
equalitySymmetry, 
independent_functionElimination, 
voidElimination, 
lambdaEquality, 
productEquality, 
inrFormation, 
addLevel, 
allFunctionality, 
productElimination, 
impliesFunctionality, 
dependent_functionElimination, 
because_Cache, 
universeEquality, 
isect_memberEquality, 
voidEquality, 
rename, 
inlFormation, 
applyEquality, 
dependent_pairFormation, 
orFunctionality, 
levelHypothesis, 
promote_hyp, 
existsFunctionality, 
andLevelFunctionality, 
existsLevelFunctionality, 
dependent_set_memberEquality, 
applyLambdaEquality, 
setElimination
Latex:
\mforall{}[X:Type]
    \mforall{}as,bs:X  List  List.  \mforall{}x:X  List.
        ((x  \mmember{}  free-dl-meet(as;bs))  \mLeftarrow{}{}\mRightarrow{}  \mexists{}u,v:X  List.  ((u  \mmember{}  as)  \mwedge{}  (v  \mmember{}  bs)  \mwedge{}  (x  =  (u  @  v))))
Date html generated:
2020_05_20-AM-08_26_59
Last ObjectModification:
2017_07_28-AM-09_13_21
Theory : lattices
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