Nuprl Lemma : lattice-fset-meet-union
∀[l:BoundedLattice]. ∀[eq:EqDecider(Point(l))]. ∀[s1,s2:fset(Point(l))].  (/\(s1 ⋃ s2) = /\(s1) ∧ /\(s2) ∈ Point(l))
Proof
Definitions occuring in Statement : 
lattice-fset-meet: /\(s)
, 
bdd-lattice: BoundedLattice
, 
lattice-meet: a ∧ b
, 
lattice-point: Point(l)
, 
fset-union: x ⋃ y
, 
fset: fset(T)
, 
deq: EqDecider(T)
, 
uall: ∀[x:A]. B[x]
, 
equal: s = t ∈ T
Definitions unfolded in proof : 
uall: ∀[x:A]. B[x]
, 
member: t ∈ T
, 
subtype_rel: A ⊆r B
, 
all: ∀x:A. B[x]
, 
so_lambda: λ2x.t[x]
, 
bdd-lattice: BoundedLattice
, 
prop: ℙ
, 
and: P ∧ Q
, 
so_apply: x[s]
, 
uimplies: b supposing a
, 
implies: P 
⇒ Q
, 
not: ¬A
, 
false: False
, 
guard: {T}
, 
squash: ↓T
, 
true: True
, 
iff: P 
⇐⇒ Q
, 
rev_implies: P 
⇐ Q
, 
lattice-fset-meet: /\(s)
, 
reduce: reduce(f;k;as)
, 
list_ind: list_ind, 
empty-fset: {}
, 
nil: []
, 
it: ⋅
, 
lattice-1: 1
, 
record-select: r.x
, 
lattice-axioms: lattice-axioms(l)
Lemmas referenced : 
fset-induction, 
lattice-point_wf, 
all_wf, 
fset_wf, 
subtype_rel_set, 
bounded-lattice-structure_wf, 
lattice-structure_wf, 
lattice-axioms_wf, 
bounded-lattice-axioms_wf, 
bounded-lattice-structure-subtype, 
equal_wf, 
lattice-fset-meet_wf, 
decidable-equal-deq, 
fset-union_wf, 
lattice-meet_wf, 
sq_stable__all, 
sq_stable__equal, 
fset-member_wf, 
istype-void, 
deq_wf, 
bdd-lattice_wf, 
squash_wf, 
true_wf, 
istype-universe, 
decidable_wf, 
empty-fset-union, 
empty-fset_wf, 
subtype_rel_self, 
iff_weakening_equal, 
lattice-1_wf, 
lattice-1-meet, 
fset-add-union, 
fset-add_wf, 
reduce_cons_lemma, 
fset-add-as-cons
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
isect_memberFormation_alt, 
cut, 
thin, 
introduction, 
extract_by_obid, 
sqequalHypSubstitution, 
isectElimination, 
hypothesisEquality, 
applyEquality, 
because_Cache, 
hypothesis, 
sqequalRule, 
dependent_functionElimination, 
lambdaEquality_alt, 
instantiate, 
productEquality, 
cumulativity, 
universeIsType, 
independent_isectElimination, 
independent_functionElimination, 
lambdaFormation_alt, 
inhabitedIsType, 
axiomEquality, 
functionIsTypeImplies, 
functionIsType, 
equalityIstype, 
imageElimination, 
equalityTransitivity, 
equalitySymmetry, 
universeEquality, 
functionEquality, 
imageMemberEquality, 
baseClosed, 
natural_numberEquality, 
productElimination, 
setElimination, 
rename, 
hyp_replacement, 
applyLambdaEquality, 
Error :memTop
Latex:
\mforall{}[l:BoundedLattice].  \mforall{}[eq:EqDecider(Point(l))].  \mforall{}[s1,s2:fset(Point(l))].
    (/\mbackslash{}(s1  \mcup{}  s2)  =  /\mbackslash{}(s1)  \mwedge{}  /\mbackslash{}(s2))
Date html generated:
2020_05_20-AM-08_44_03
Last ObjectModification:
2020_01_31-AM-10_28_54
Theory : lattices
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