Nuprl Lemma : setmem-set-add

∀a,b,x:coSet{i:l}.  ((x ∈ a + b) ⇐⇒ (x ∈ a) ∨ (x ∈ b))


Proof




Definitions occuring in Statement :  set-add: a + b,  setmem: (x ∈ s),  coSet: coSet{i:l},  all: ∀x:A. B[x],  iff: P ⇐⇒ Q,  or: P ∨ Q
Definitions unfolded in proof :  all: ∀x:A. B[x],  member: t ∈ T,  subtype_rel: A ⊆r B,  iff: P ⇐⇒ Q,  and: P ∧ Q,  implies: P ⇒ Q,  set-add: a + b,  mk-coset: mk-coset(T;f),  uall: ∀[x:A]. B[x],  top: Top,  exists: ∃x:A. B[x],  prop: ℙ,  rev_implies: P ⇐ Q,  or: P ∨ Q,  so_lambda: λ2x.t[x],  so_apply: x[s],  guard: {T}
Lemmas referenced :  subtype_coSet,  coSet_subtype,  setmem-mk-coset,  setmem_wf,  set-add_wf,  mk-coset_wf,  or_wf,  coSet_wf,  seteq_wf,  exists_wf,  equal_wf
Rules used in proof :  sqequalSubstitution,  sqequalTransitivity,  computationStep,  sqequalReflexivity,  lambdaFormation,  hypothesis_subsumption,  cut,  introduction,  extract_by_obid,  hypothesis,  hypothesisEquality,  applyEquality,  sqequalHypSubstitution,  sqequalRule,  productElimination,  thin,  independent_pairFormation,  isectElimination,  isect_memberEquality,  voidElimination,  voidEquality,  because_Cache,  unionElimination,  inlFormation,  dependent_pairFormation,  lambdaEquality,  inrFormation,  inlEquality,  equalityTransitivity,  equalitySymmetry,  unionEquality,  dependent_functionElimination,  independent_functionElimination,  inrEquality

Latex:
\mforall{}a,b,x:coSet\{i:l\}.    ((x  \mmember{}  a  +  b)  \mLeftarrow{}{}\mRightarrow{}  (x  \mmember{}  a)  \mvee{}  (x  \mmember{}  b))



Date html generated: 2019_10_31-AM-06_33_24
Last ObjectModification: 2018_08_21-PM-02_01_22

Theory : constructive!set!theory


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