Nuprl Lemma : face_lattice-fset-join-eq-1

I:fset(ℕ). ∀s:fset(Point(face_lattice(I))).
  (\/(s) 1 ∈ Point(face_lattice(I)) ⇐⇒ ∃x:Point(face_lattice(I)). (x ∈ s ∧ (x 1 ∈ Point(face_lattice(I)))))


Proof




Definitions occuring in Statement :  face_lattice-deq: face_lattice-deq() face_lattice: face_lattice(I) lattice-fset-join: \/(s) lattice-1: 1 lattice-point: Point(l) fset-member: a ∈ s fset: fset(T) nat: all: x:A. B[x] exists: x:A. B[x] iff: ⇐⇒ Q and: P ∧ Q equal: t ∈ T
Definitions unfolded in proof :  all: x:A. B[x] uall: [x:A]. B[x] member: t ∈ T subtype_rel: A ⊆B bdd-distributive-lattice: BoundedDistributiveLattice so_lambda: λ2x.t[x] prop: and: P ∧ Q so_apply: x[s] uimplies: supposing a implies:  Q iff: ⇐⇒ Q rev_implies:  Q not: ¬A false: False guard: {T} exists: x:A. B[x] squash: T true: True cand: c∧ B sq_stable: SqStable(P) decidable: Dec(P) or: P ∨ Q empty-fset: {} lattice-fset-join: \/(s) top: Top fset-add: fset-add(eq;x;s) uiff: uiff(P;Q)
Lemmas referenced :  fset-induction lattice-point_wf face_lattice_wf subtype_rel_set bounded-lattice-structure_wf lattice-structure_wf lattice-axioms_wf bounded-lattice-structure-subtype bounded-lattice-axioms_wf uall_wf equal_wf lattice-meet_wf lattice-join_wf face_lattice-deq_wf iff_wf lattice-fset-join_wf decidable__equal_face_lattice lattice-1_wf bdd-distributive-lattice_wf exists_wf fset-member_wf fset_wf sq_stable__iff sq_stable__equal empty-fset_wf fset-add_wf not_wf nat_wf squash_wf true_wf deq_wf iff_weakening_equal decidable__fset-member face-lattice-0-not-1 reduce_nil_lemma member-empty-fset bdd-distributive-lattice-subtype-bdd-lattice fset-singleton_wf face_lattice-1-join-irreducible lattice-fset-join-union lattice-fset-join-singleton fset-union_wf member-fset-union member-fset-singleton or_wf
Rules used in proof :  sqequalSubstitution sqequalTransitivity computationStep sqequalReflexivity lambdaFormation cut introduction extract_by_obid sqequalHypSubstitution isectElimination thin hypothesisEquality hypothesis applyEquality sqequalRule instantiate lambdaEquality productEquality cumulativity universeEquality because_Cache independent_isectElimination dependent_functionElimination independent_functionElimination setElimination rename independent_pairFormation isect_memberFormation voidElimination productElimination imageElimination equalityTransitivity equalitySymmetry equalityUniverse levelHypothesis natural_numberEquality imageMemberEquality baseClosed dependent_pairFormation unionElimination isect_memberEquality voidEquality inlFormation inrFormation addLevel orFunctionality promote_hyp

Latex:
\mforall{}I:fset(\mBbbN{}).  \mforall{}s:fset(Point(face\_lattice(I))).
    (\mbackslash{}/(s)  =  1  \mLeftarrow{}{}\mRightarrow{}  \mexists{}x:Point(face\_lattice(I)).  (x  \mmember{}  s  \mwedge{}  (x  =  1)))



Date html generated: 2017_10_05-AM-01_10_15
Last ObjectModification: 2017_03_02-PM-10_27_18

Theory : cubical!type!theory


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