Nuprl Lemma : set-equal-cons

∀[T:Type]
  ∀u:T. ∀v,bs:T List.
    (set-equal(T;[u / v];bs) ⇐⇒ ∃cs,ds:T List. ((bs = (cs @ [u / ds]) ∈ (T List)) ∧ set-equal(T;v;cs @ ds))) supposing 
       (no_repeats(T;bs) and 
       no_repeats(T;[u / v]))


Proof




Definitions occuring in Statement :  set-equal: set-equal(T;x;y),  no_repeats: no_repeats(T;l),  append: as @ bs,  cons: [a / b],  list: T List,  uimplies: b supposing a,  uall: ∀[x:A]. B[x],  all: ∀x:A. B[x],  exists: ∃x:A. B[x],  iff: P ⇐⇒ Q,  and: P ∧ Q,  universe: Type,  equal: s = t ∈ T
Definitions unfolded in proof :  uall: ∀[x:A]. B[x],  all: ∀x:A. B[x],  uimplies: b supposing a,  member: t ∈ T,  implies: P ⇒ Q,  iff: P ⇐⇒ Q,  and: P ∧ Q,  prop: ℙ,  rev_implies: P ⇐ Q,  so_lambda: λ2x.t[x],  top: Top,  so_apply: x[s],  set-equal: set-equal(T;x;y),  or: P ∨ Q,  exists: ∃x:A. B[x],  append: as @ bs,  so_lambda: so_lambda(x,y,z.t[x; y; z]),  so_apply: x[s1;s2;s3],  cand: A c∧ B,  guard: {T},  uiff: uiff(P;Q),  not: ¬A,  false: False
Lemmas referenced :  no_repeats_witness,  cons_wf,  set-equal_wf,  exists_wf,  list_wf,  equal_wf,  append_wf,  length_wf,  length-append,  no_repeats_wf,  cons_member,  l_member_wf,  l_member_decomp,  list_ind_cons_lemma,  list_ind_nil_lemma,  member_append,  or_wf,  iff_wf,  no_repeats_cons,  no_repeats-append,  l_disjoint_cons,  length_wf_nat,  nat_wf
Rules used in proof :  sqequalSubstitution,  sqequalTransitivity,  computationStep,  sqequalReflexivity,  isect_memberFormation,  lambdaFormation,  cut,  introduction,  extract_by_obid,  sqequalHypSubstitution,  isectElimination,  thin,  hypothesisEquality,  cumulativity,  hypothesis,  independent_functionElimination,  rename,  because_Cache,  independent_pairFormation,  sqequalRule,  lambdaEquality,  productEquality,  applyLambdaEquality,  isect_memberEquality,  voidElimination,  voidEquality,  universeEquality,  dependent_functionElimination,  productElimination,  inlFormation,  dependent_pairFormation,  equalitySymmetry,  hyp_replacement,  promote_hyp,  addLevel,  orFunctionality,  impliesFunctionality,  inrFormation,  unionElimination,  independent_isectElimination,  dependent_set_memberEquality,  setElimination

Latex:
\mforall{}[T:Type]
    \mforall{}u:T.  \mforall{}v,bs:T  List.
        (set-equal(T;[u  /  v];bs)
              \mLeftarrow{}{}\mRightarrow{}  \mexists{}cs,ds:T  List.  ((bs  =  (cs  @  [u  /  ds]))  \mwedge{}  set-equal(T;v;cs  @  ds)))  supposing 
              (no\_repeats(T;bs)  and 
              no\_repeats(T;[u  /  v]))



Date html generated: 2017_04_17-AM-07_37_04
Last ObjectModification: 2017_02_27-PM-04_12_23

Theory : list_1


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