Nuprl Lemma : remove-repeats_property

[T:Type]
  ∀eq:EqDecider(T). ∀L:T List.  (no_repeats(T;remove-repeats(eq;L)) ∧ (∀a:T. ((a ∈ remove-repeats(eq;L)) ⇐⇒ (a ∈ L))))


Proof




Definitions occuring in Statement :  remove-repeats: remove-repeats(eq;L) no_repeats: no_repeats(T;l) l_member: (x ∈ l) list: List deq: EqDecider(T) uall: [x:A]. B[x] all: x:A. B[x] iff: ⇐⇒ Q and: P ∧ Q universe: Type
Definitions unfolded in proof :  uall: [x:A]. B[x] all: x:A. B[x] member: t ∈ T so_lambda: λ2x.t[x] prop: and: P ∧ Q so_apply: x[s] iff: ⇐⇒ Q rev_implies:  Q implies:  Q remove-repeats: remove-repeats(eq;L) so_lambda: so_lambda(x,y,z.t[x; y; z]) top: Top so_apply: x[s1;s2;s3] cand: c∧ B deq: EqDecider(T) uiff: uiff(P;Q) uimplies: supposing a not: ¬A false: False eqof: eqof(d) or: P ∨ Q guard: {T} decidable: Dec(P)
Lemmas referenced :  list_induction no_repeats_wf remove-repeats_wf all_wf iff_wf l_member_wf list_wf list_ind_nil_lemma no_repeats_nil nil_wf list_ind_cons_lemma no_repeats_cons filter_wf5 bnot_wf no_repeats_filter cons_wf deq_wf member_filter not_wf assert_wf member_wf eqof_wf equal_wf iff_transitivity iff_weakening_uiff assert_of_bnot safe-assert-deq cons_member decidable-equal-deq
Rules used in proof :  sqequalSubstitution sqequalTransitivity computationStep sqequalReflexivity isect_memberFormation lambdaFormation cut thin introduction extract_by_obid sqequalHypSubstitution isectElimination hypothesisEquality sqequalRule lambdaEquality productEquality cumulativity hypothesis independent_functionElimination dependent_functionElimination isect_memberEquality voidElimination voidEquality independent_pairFormation because_Cache rename productElimination applyEquality setElimination setEquality independent_isectElimination universeEquality addLevel impliesFunctionality andLevelFunctionality levelHypothesis impliesLevelFunctionality unionElimination inlFormation inrFormation

Latex:
\mforall{}[T:Type]
    \mforall{}eq:EqDecider(T).  \mforall{}L:T  List.
        (no\_repeats(T;remove-repeats(eq;L))  \mwedge{}  (\mforall{}a:T.  ((a  \mmember{}  remove-repeats(eq;L))  \mLeftarrow{}{}\mRightarrow{}  (a  \mmember{}  L))))



Date html generated: 2017_04_17-AM-09_10_16
Last ObjectModification: 2017_02_27-PM-05_18_28

Theory : decidable!equality


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