Nuprl Lemma : setmem-set-add

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


Proof




Definitions occuring in Statement :  set-add: b setmem: (x ∈ s) coSet: coSet{i:l} all: x:A. B[x] iff: ⇐⇒ Q or: P ∨ Q
Definitions unfolded in proof :  all: x:A. B[x] member: t ∈ T subtype_rel: A ⊆B iff: ⇐⇒ Q and: P ∧ Q implies:  Q set-add: b mk-coset: mk-coset(T;f) uall: [x:A]. B[x] top: Top exists: x:A. B[x] prop: rev_implies:  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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