Nuprl Lemma : fset-ac-glb-is-glb
∀[T:Type]. ∀[eq:EqDecider(T)]. ∀[ac1,ac2:{ac:fset(fset(T))| ↑fset-antichain(eq;ac)} ].
  greatest-lower-bound({ac:fset(fset(T))| ↑fset-antichain(eq;ac)} ac1,ac2.fset-ac-le(eq;ac1;ac2);ac1;ac2;fset-ac-glb(eq\000C;ac1;ac2))
Proof
Definitions occuring in Statement : 
fset-ac-glb: fset-ac-glb(eq;ac1;ac2), 
fset-ac-le: fset-ac-le(eq;ac1;ac2), 
fset-antichain: fset-antichain(eq;ac), 
fset: fset(T), 
deq: EqDecider(T), 
greatest-lower-bound: greatest-lower-bound(T;x,y.R[x; y];a;b;c), 
assert: ↑b, 
uall: ∀[x:A]. B[x], 
set: {x:A| B[x]} , 
universe: Type
Definitions unfolded in proof : 
uall: ∀[x:A]. B[x], 
member: t ∈ T, 
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-ac-glb: fset-ac-glb(eq;ac1;ac2), 
so_lambda: λ2x y.t[x; y], 
so_apply: x[s1;s2], 
uimplies: b supposing a, 
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, 
fset-union: x ⋃ y, 
l-union: as ⋃ bs, 
reduce: reduce(f;k;as), 
list_ind: list_ind
Lemmas referenced : 
fset-ac-le_wf, 
assert_witness, 
fset-null_wf, 
fset_wf, 
fset-filter_wf, 
bnot_wf, 
deq-f-subset_wf, 
fset-ac-glb_wf, 
assert_wf, 
fset-antichain_wf, 
set_wf, 
deq_wf, 
fset-all-iff, 
deq-fset_wf, 
iff_weakening_uiff, 
fset-all_wf, 
fset-minimals_wf, 
f-proper-subset-dec_wf, 
f-union_wf, 
fset-image_wf, 
fset-union_wf, 
uall_wf, 
isect_wf, 
fset-member_wf, 
assert_of_bnot, 
bool_wf, 
all_wf, 
iff_wf, 
f-subset_wf, 
member-fset-minimals, 
assert-fset-null, 
not_wf, 
equal-wf-T-base, 
member-f-union, 
member-fset-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-implies, 
fset-extensionality, 
fset-member_witness, 
false_wf, 
f-union-subset, 
equal_wf
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, 
dependent_set_memberEquality, 
independent_functionElimination, 
setEquality, 
dependent_functionElimination, 
isect_memberEquality, 
universeEquality, 
functionEquality, 
functionExtensionality, 
independent_isectElimination, 
addLevel, 
impliesFunctionality, 
baseClosed, 
equalityTransitivity, 
equalitySymmetry, 
imageElimination, 
hyp_replacement, 
applyLambdaEquality, 
voidElimination, 
voidEquality, 
natural_numberEquality, 
imageMemberEquality, 
dependent_pairFormation, 
productEquality
Latex:
\mforall{}[T:Type].  \mforall{}[eq:EqDecider(T)].  \mforall{}[ac1,ac2:\{ac:fset(fset(T))|  \muparrow{}fset-antichain(eq;ac)\}  ].
    greatest-lower-bound(\{ac:fset(fset(T))| 
                                                \muparrow{}fset-antichain(eq;ac)\}  ;ac1,ac2.fset-ac-le(eq;ac1;ac2);ac1;ac2;fset-ac-glb(\000Ceq;ac1;ac2))
Date html generated:
2017_04_17-AM-09_24_17
Last ObjectModification:
2017_02_27-PM-05_27_17
Theory : finite!sets
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