Nuprl Lemma : fset-ac-lub-covers
∀[T:Type]. ∀[eq:EqDecider(T)]. ∀[x,y:{ac:fset(fset(T))| ↑fset-antichain(eq;ac)} ]. ∀[a:fset(T)].
  (((↑ac-covers(eq;x;a)) ∨ (↑ac-covers(eq;y;a))) 
⇒ (↑ac-covers(eq;fset-ac-lub(eq;x;y);a)))
Proof
Definitions occuring in Statement : 
fset-ac-lub: fset-ac-lub(eq;ac1;ac2)
, 
ac-covers: ac-covers(eq;ac;x)
, 
fset-antichain: fset-antichain(eq;ac)
, 
fset: fset(T)
, 
deq: EqDecider(T)
, 
assert: ↑b
, 
uall: ∀[x:A]. B[x]
, 
implies: P 
⇒ Q
, 
or: P ∨ Q
, 
set: {x:A| B[x]} 
, 
universe: Type
Definitions unfolded in proof : 
uall: ∀[x:A]. B[x]
, 
member: t ∈ T
, 
implies: P 
⇒ Q
, 
all: ∀x:A. B[x]
, 
so_lambda: λ2x y.t[x; y]
, 
so_apply: x[s1;s2]
, 
iff: P 
⇐⇒ Q
, 
and: P ∧ Q
, 
uiff: uiff(P;Q)
, 
uimplies: b supposing a
, 
so_lambda: λ2x.t[x]
, 
so_apply: x[s]
, 
exists: ∃x:A. B[x]
, 
prop: ℙ
, 
subtype_rel: A ⊆r B
, 
rev_uimplies: rev_uimplies(P;Q)
, 
or: P ∨ Q
, 
squash: ↓T
, 
rev_implies: P 
⇐ Q
, 
cand: A c∧ B
, 
fset-ac-lub: fset-ac-lub(eq;ac1;ac2)
, 
guard: {T}
Lemmas referenced : 
deq_wf, 
set_wf, 
assert_witness, 
ac-covers_wf, 
or_wf, 
f-subset_transitivity, 
member-fset-union, 
fset-antichain_wf, 
assert_wf, 
fset-ac-lub_wf, 
f-subset_wf, 
fset-member_wf, 
and_wf, 
exists_wf, 
squash_wf, 
assert-ac-covers, 
f-proper-subset-dec_wf, 
fset-minimals_wf, 
fset-ac-le-iff, 
deq-fset_wf, 
fset_wf, 
fset-union_wf, 
fset-minimals-ac-le
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
isect_memberFormation, 
introduction, 
cut, 
lambdaFormation, 
lemma_by_obid, 
sqequalHypSubstitution, 
isectElimination, 
thin, 
hypothesisEquality, 
dependent_functionElimination, 
hypothesis, 
setElimination, 
rename, 
because_Cache, 
sqequalRule, 
lambdaEquality, 
productElimination, 
independent_functionElimination, 
addLevel, 
orFunctionality, 
independent_isectElimination, 
levelHypothesis, 
promote_hyp, 
applyEquality, 
setEquality, 
unionElimination, 
imageElimination, 
inlFormation, 
dependent_pairFormation, 
independent_pairFormation, 
productEquality, 
imageMemberEquality, 
baseClosed, 
inrFormation, 
orLevelFunctionality, 
isect_memberEquality, 
universeEquality
Latex:
\mforall{}[T:Type].  \mforall{}[eq:EqDecider(T)].  \mforall{}[x,y:\{ac:fset(fset(T))|  \muparrow{}fset-antichain(eq;ac)\}  ].  \mforall{}[a:fset(T)].
    (((\muparrow{}ac-covers(eq;x;a))  \mvee{}  (\muparrow{}ac-covers(eq;y;a)))  {}\mRightarrow{}  (\muparrow{}ac-covers(eq;fset-ac-lub(eq;x;y);a)))
Date html generated:
2016_05_14-PM-03_48_51
Last ObjectModification:
2016_01_20-PM-09_08_23
Theory : finite!sets
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