Nuprl Lemma : ss-mem-open-and

∀[X:SeparationSpace]. ∀A,B:Open(X). ∀x:Point(X).  (x ∈ A ⋂ B ⇐⇒ x ∈ A ∧ x ∈ B)


Proof




Definitions occuring in Statement :  ss-open-and: A ⋂ B,  ss-mem-open: x ∈ O,  ss-open: Open(X),  ss-point: Point(ss),  separation-space: SeparationSpace,  uall: ∀[x:A]. B[x],  all: ∀x:A. B[x],  iff: P ⇐⇒ Q,  and: P ∧ Q
Definitions unfolded in proof :  uall: ∀[x:A]. B[x],  all: ∀x:A. B[x],  iff: P ⇐⇒ Q,  and: P ∧ Q,  implies: P ⇒ Q,  ss-open-and: A ⋂ B,  ss-mem-open: x ∈ O,  exists: ∃x:A. B[x],  member: t ∈ T,  squash: ↓T,  prop: ℙ,  true: True,  subtype_rel: A ⊆r B,  uimplies: b supposing a,  guard: {T},  uiff: uiff(P;Q),  ss-open: Open(X),  rev_implies: P ⇐ Q,  cand: A c∧ B,  so_lambda: λ2x.t[x],  so_apply: x[s],  rev_uimplies: rev_uimplies(P;Q)
Lemmas referenced :  ss-mem-basic_wf,  squash_wf,  true_wf,  ss-point_wf,  ss-basic_wf,  subtype_rel_self,  iff_weakening_equal,  ss-mem-basic-and,  ss-mem-open_wf,  ss-open-and_wf,  ss-basic-and_wf,  equal_wf,  exists_wf,  ss-open_wf,  separation-space_wf
Rules used in proof :  sqequalSubstitution,  sqequalTransitivity,  computationStep,  sqequalReflexivity,  isect_memberFormation,  lambdaFormation,  independent_pairFormation,  sqequalHypSubstitution,  sqequalRule,  productElimination,  thin,  cut,  applyEquality,  lambdaEquality,  imageElimination,  introduction,  extract_by_obid,  isectElimination,  hypothesisEquality,  equalityTransitivity,  hypothesis,  equalitySymmetry,  because_Cache,  natural_numberEquality,  imageMemberEquality,  baseClosed,  instantiate,  universeEquality,  independent_isectElimination,  independent_functionElimination,  dependent_functionElimination,  dependent_pairFormation,  productEquality,  rename

Latex:
\mforall{}[X:SeparationSpace].  \mforall{}A,B:Open(X).  \mforall{}x:Point(X).    (x  \mmember{}  A  \mcap{}  B  \mLeftarrow{}{}\mRightarrow{}  x  \mmember{}  A  \mwedge{}  x  \mmember{}  B)



Date html generated: 2020_05_20-PM-01_22_37
Last ObjectModification: 2018_07_06-PM-04_56_17

Theory : intuitionistic!topology


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