Nuprl Lemma : append_cancel

∀[A:Type]. ∀[as,bs,cs:A List].  bs = cs ∈ (A List) supposing (as @ bs) = (as @ cs) ∈ (A List)


Proof




Definitions occuring in Statement :  append: as @ bs,  list: T List,  uimplies: b supposing a,  uall: ∀[x:A]. B[x],  universe: Type,  equal: s = t ∈ T
Definitions unfolded in proof :  uall: ∀[x:A]. B[x],  member: t ∈ T,  so_lambda: λ2x.t[x],  uimplies: b supposing a,  prop: ℙ,  so_apply: x[s],  implies: P ⇒ Q,  append: as @ bs,  all: ∀x:A. B[x],  so_lambda: so_lambda(x,y,z.t[x; y; z]),  top: Top,  so_apply: x[s1;s2;s3],  guard: {T},  and: P ∧ Q
Lemmas referenced :  list_induction,  uall_wf,  list_wf,  isect_wf,  equal_wf,  append_wf,  list_ind_nil_lemma,  list_ind_cons_lemma,  cons_wf,  reduce_tl_cons_lemma,  and_wf,  tl_wf
Rules used in proof :  sqequalSubstitution,  sqequalTransitivity,  computationStep,  sqequalReflexivity,  isect_memberFormation,  introduction,  cut,  thin,  extract_by_obid,  sqequalHypSubstitution,  isectElimination,  hypothesisEquality,  sqequalRule,  lambdaEquality,  cumulativity,  hypothesis,  because_Cache,  independent_functionElimination,  dependent_functionElimination,  isect_memberEquality,  voidElimination,  voidEquality,  axiomEquality,  equalityTransitivity,  equalitySymmetry,  lambdaFormation,  rename,  universeEquality,  dependent_set_memberEquality,  independent_pairFormation,  applyLambdaEquality,  setElimination,  productElimination,  independent_isectElimination

Latex:
\mforall{}[A:Type].  \mforall{}[as,bs,cs:A  List].    bs  =  cs  supposing  (as  @  bs)  =  (as  @  cs)



Date html generated: 2017_04_17-AM-08_13_18
Last ObjectModification: 2017_02_27-PM-04_39_04

Theory : list_1


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