Nuprl Lemma : member-fset-pair

[T:Type]. ∀eq:EqDecider(T). ∀x,y,z:T.  uiff(z ∈ {x,y};(z x ∈ T) ∨ (z y ∈ T))


Proof




Definitions occuring in Statement :  fset-pair: {a,b} fset-member: a ∈ s deq: EqDecider(T) uiff: uiff(P;Q) uall: [x:A]. B[x] all: x:A. B[x] or: P ∨ Q universe: Type equal: t ∈ T
Definitions unfolded in proof :  uall: [x:A]. B[x] all: x:A. B[x] member: t ∈ T implies:  Q guard: {T} fset-pair: {a,b} fset-member: a ∈ s top: Top uiff: uiff(P;Q) and: P ∧ Q uimplies: supposing a prop: or: P ∨ Q iff: ⇐⇒ Q assert: b ifthenelse: if then else fi  bfalse: ff rev_implies:  Q eqof: eqof(d) decidable: Dec(P) not: ¬A false: False
Lemmas referenced :  deq-implies deq_member_cons_lemma deq_member_nil_lemma deq_wf or_wf equal_wf bor_wf eqof_wf bfalse_wf assert_wf false_wf uiff_wf assert_witness iff_transitivity iff_weakening_uiff assert_of_bor safe-assert-deq
Rules used in proof :  sqequalSubstitution sqequalTransitivity computationStep sqequalReflexivity isect_memberFormation lambdaFormation cut introduction extract_by_obid sqequalHypSubstitution isectElimination thin because_Cache independent_functionElimination hypothesis sqequalRule dependent_functionElimination isect_memberEquality voidElimination voidEquality hypothesisEquality cumulativity universeEquality independent_pairFormation applyEquality addLevel productElimination rename independent_isectElimination orFunctionality unionElimination inlFormation inrFormation equalitySymmetry

Latex:
\mforall{}[T:Type].  \mforall{}eq:EqDecider(T).  \mforall{}x,y,z:T.    uiff(z  \mmember{}  \{x,y\};(z  =  x)  \mvee{}  (z  =  y))



Date html generated: 2017_04_17-AM-09_18_59
Last ObjectModification: 2017_02_27-PM-05_22_29

Theory : finite!sets


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