Nuprl Lemma : permutation-cons

[A:Type]
  ∀x:A. ∀L1,L2:A List.
    (permutation(A;[x L1];L2) ⇐⇒ ∃as,bs:A List. ((L2 (as [x bs]) ∈ (A List)) ∧ permutation(A;L1;as bs)))


Proof




Definitions occuring in Statement :  permutation: permutation(T;L1;L2) append: as bs cons: [a b] list: List uall: [x:A]. B[x] all: x:A. B[x] exists: x:A. B[x] iff: ⇐⇒ Q and: P ∧ Q universe: Type equal: t ∈ T
Definitions unfolded in proof :  uall: [x:A]. B[x] all: x:A. B[x] iff: ⇐⇒ Q and: P ∧ Q implies:  Q member: t ∈ T prop: rev_implies:  Q exists: x:A. B[x] so_lambda: λ2x.t[x] top: Top so_apply: x[s] l_contains: A ⊆ B l_all: (∀x∈L.P[x]) int_seg: {i..j-} lelt: i ≤ j < k le: A ≤ B less_than': less_than'(a;b) false: False not: ¬A nat_plus: + less_than: a < b squash: T true: True guard: {T} decidable: Dec(P) or: P ∨ Q uiff: uiff(P;Q) uimplies: supposing a satisfiable_int_formula: satisfiable_int_formula(fmla) select: L[n] cons: [a b] append: as bs so_lambda: so_lambda(x,y,z.t[x; y; z]) so_apply: x[s1;s2;s3] cand: c∧ B
Lemmas referenced :  permutation_wf cons_wf exists_wf list_wf equal_wf append_wf length_wf length-append permutation_inversion permutation-contains length_of_cons_lemma false_wf add_nat_plus length_wf_nat less_than_wf nat_plus_wf nat_plus_properties decidable__lt add-is-int-iff satisfiable-full-omega-tt intformand_wf intformnot_wf intformless_wf itermConstant_wf itermVar_wf itermAdd_wf intformeq_wf int_formula_prop_and_lemma int_formula_prop_not_lemma int_formula_prop_less_lemma int_term_value_constant_lemma int_term_value_var_lemma int_term_value_add_lemma int_formula_prop_eq_lemma int_formula_prop_wf lelt_wf l_member_decomp list_ind_cons_lemma list_ind_nil_lemma permutation_transitivity permutation-rotate nil_wf permutation_weakening append_functionality_wrt_permutation cons_cancel_wrt_permutation
Rules used in proof :  sqequalSubstitution sqequalTransitivity computationStep sqequalReflexivity isect_memberFormation lambdaFormation independent_pairFormation cut introduction extract_by_obid sqequalHypSubstitution isectElimination thin cumulativity hypothesisEquality hypothesis productElimination sqequalRule lambdaEquality productEquality applyLambdaEquality isect_memberEquality voidElimination voidEquality universeEquality dependent_functionElimination independent_functionElimination because_Cache dependent_set_memberEquality natural_numberEquality imageMemberEquality baseClosed equalityTransitivity equalitySymmetry setElimination rename unionElimination pointwiseFunctionality promote_hyp baseApply closedConclusion independent_isectElimination dependent_pairFormation int_eqEquality intEquality computeAll addEquality hyp_replacement

Latex:
\mforall{}[A:Type]
    \mforall{}x:A.  \mforall{}L1,L2:A  List.
        (permutation(A;[x  /  L1];L2)
        \mLeftarrow{}{}\mRightarrow{}  \mexists{}as,bs:A  List.  ((L2  =  (as  @  [x  /  bs]))  \mwedge{}  permutation(A;L1;as  @  bs)))



Date html generated: 2017_04_17-AM-08_23_42
Last ObjectModification: 2017_02_27-PM-04_45_25

Theory : list_1


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