Nuprl Lemma : fset-constrained-ac-glb-is-glb
∀[T:Type]. ∀[eq:EqDecider(T)]. ∀[P:fset(T) ⟶ 𝔹].
  ∀[ac1,ac2:{ac:fset(fset(T))| (↑fset-antichain(eq;ac)) ∧ fset-all(ac;a.P[a])} ].
    greatest-lower-bound({ac:fset(fset(T))| 
                          (↑fset-antichain(eq;ac)) ∧ fset-all(ac;a.P[a])} ac1,ac2.fset-ac-le(eq;ac1;ac2);ac1;ac2;glb(P;\000Cac1;ac2)) 
  supposing ∀x,y:fset(T).  (y ⊆ x 
⇒ (↑(P x)) 
⇒ (↑(P y)))
Proof
Definitions occuring in Statement : 
fset-constrained-ac-glb: glb(P;ac1;ac2)
, 
fset-ac-le: fset-ac-le(eq;ac1;ac2)
, 
fset-antichain: fset-antichain(eq;ac)
, 
fset-all: fset-all(s;x.P[x])
, 
f-subset: xs ⊆ ys
, 
fset: fset(T)
, 
deq: EqDecider(T)
, 
greatest-lower-bound: greatest-lower-bound(T;x,y.R[x; y];a;b;c)
, 
assert: ↑b
, 
bool: 𝔹
, 
uimplies: b supposing a
, 
uall: ∀[x:A]. B[x]
, 
so_apply: x[s]
, 
all: ∀x:A. B[x]
, 
implies: P 
⇒ Q
, 
and: P ∧ Q
, 
set: {x:A| B[x]} 
, 
apply: f a
, 
function: x:A ⟶ B[x]
, 
universe: Type
Definitions unfolded in proof : 
uall: ∀[x:A]. B[x]
, 
member: t ∈ T
, 
uimplies: b supposing a
, 
greatest-lower-bound: greatest-lower-bound(T;x,y.R[x; y];a;b;c)
, 
and: P ∧ Q
, 
cand: A c∧ B
, 
all: ∀x:A. B[x]
, 
implies: P 
⇒ Q
, 
prop: ℙ
, 
fset-ac-le: fset-ac-le(eq;ac1;ac2)
, 
fset-all: fset-all(s;x.P[x])
, 
so_lambda: λ2x.t[x]
, 
subtype_rel: A ⊆r B
, 
so_apply: x[s]
, 
fset-constrained-ac-glb: glb(P;ac1;ac2)
, 
so_lambda: λ2x y.t[x; y]
, 
so_apply: x[s1;s2]
, 
iff: P 
⇐⇒ Q
, 
rev_implies: P 
⇐ Q
, 
uiff: uiff(P;Q)
, 
rev_uimplies: rev_uimplies(P;Q)
, 
not: ¬A
, 
squash: ↓T
, 
false: False
, 
exists: ∃x:A. B[x]
, 
guard: {T}
, 
top: Top
, 
true: True
, 
sq_stable: SqStable(P)
Lemmas referenced : 
fset-ac-le_wf, 
assert_witness, 
fset-null_wf, 
fset_wf, 
fset-filter_wf, 
bnot_wf, 
deq-f-subset_wf, 
fset-constrained-ac-glb_wf, 
assert_wf, 
fset-antichain_wf, 
fset-all_wf, 
set_wf, 
all_wf, 
f-subset_wf, 
bool_wf, 
deq_wf, 
fset-all-iff, 
deq-fset_wf, 
iff_weakening_uiff, 
fset-minimals_wf, 
f-proper-subset-dec_wf, 
f-union_wf, 
fset-constrained-image_wf, 
fset-union_wf, 
uall_wf, 
isect_wf, 
fset-member_wf, 
assert_of_bnot, 
iff_wf, 
member-fset-minimals, 
assert-fset-null, 
not_wf, 
equal-wf-T-base, 
member-f-union, 
member-fset-constrained-image-iff, 
member-fset-filter, 
assert-deq-f-subset, 
f-subset-union, 
mem_empty_lemma, 
squash_wf, 
true_wf, 
fset-union-commutes, 
iff_weakening_equal, 
fset-ac-le_transitivity, 
fset-minimals-ac-le, 
fset-ac-le-implies2, 
f-union-subset, 
equal_wf, 
sq_stable_from_decidable, 
decidable__assert
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
isect_memberFormation, 
introduction, 
cut, 
independent_pairFormation, 
hypothesis, 
lambdaFormation, 
extract_by_obid, 
sqequalHypSubstitution, 
isectElimination, 
thin, 
cumulativity, 
hypothesisEquality, 
setElimination, 
rename, 
because_Cache, 
sqequalRule, 
productElimination, 
independent_pairEquality, 
lambdaEquality, 
applyEquality, 
functionExtensionality, 
setEquality, 
productEquality, 
independent_functionElimination, 
dependent_functionElimination, 
isect_memberEquality, 
functionEquality, 
equalityTransitivity, 
equalitySymmetry, 
universeEquality, 
independent_isectElimination, 
addLevel, 
impliesFunctionality, 
baseClosed, 
imageElimination, 
hyp_replacement, 
applyLambdaEquality, 
voidElimination, 
voidEquality, 
natural_numberEquality, 
imageMemberEquality, 
dependent_pairFormation
Latex:
\mforall{}[T:Type].  \mforall{}[eq:EqDecider(T)].  \mforall{}[P:fset(T)  {}\mrightarrow{}  \mBbbB{}].
    \mforall{}[ac1,ac2:\{ac:fset(fset(T))|  (\muparrow{}fset-antichain(eq;ac))  \mwedge{}  fset-all(ac;a.P[a])\}  ].
        greatest-lower-bound(\{ac:fset(fset(T))| 
                                                    (\muparrow{}fset-antichain(eq;ac))  \mwedge{}  fset-all(ac;a.P[a])\}  ;ac1,ac2.fset-ac-le(eq;ac1\000C;ac2);ac1;ac2;...) 
    supposing  \mforall{}x,y:fset(T).    (y  \msubseteq{}  x  {}\mRightarrow{}  (\muparrow{}(P  x))  {}\mRightarrow{}  (\muparrow{}(P  y)))
Date html generated:
2017_04_17-AM-09_25_00
Last ObjectModification:
2017_02_27-PM-05_27_11
Theory : finite!sets
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