Nuprl Lemma : l_before_l_index_le

[T:Type]
  ∀dT:EqDecider(T). ∀L:T List. ∀x,y:T.
    ((x ∈ L)  (y ∈ L)  before y ∈ L ∨ (x y ∈ T) supposing index(L;x) ≤ index(L;y))


Proof




Definitions occuring in Statement :  l_index: index(L;x) l_before: before y ∈ l l_member: (x ∈ l) list: List deq: EqDecider(T) uimplies: supposing a uall: [x:A]. B[x] le: A ≤ B all: x:A. B[x] implies:  Q or: P ∨ Q universe: Type equal: t ∈ T
Definitions unfolded in proof :  uall: [x:A]. B[x] all: x:A. B[x] implies:  Q uimplies: supposing a member: t ∈ T le: A ≤ B and: P ∧ Q decidable: Dec(P) or: P ∨ Q subtype_rel: A ⊆B int_seg: {i..j-} prop: squash: T not: ¬A satisfiable_int_formula: satisfiable_int_formula(fmla) exists: x:A. B[x] false: False top: Top cand: c∧ B ge: i ≥  guard: {T} nat: lelt: i ≤ j < k true: True iff: ⇐⇒ Q
Lemmas referenced :  le_witness_for_triv decidable__lt istype-le l_index_wf l_member_wf list_wf deq_wf istype-universe l_before_l_index l_before_wf select_wf squash_wf le_wf less_than_wf length_wf istype-int decidable__equal_int full-omega-unsat intformand_wf intformnot_wf intformeq_wf itermVar_wf intformless_wf intformle_wf int_formula_prop_and_lemma istype-void int_formula_prop_not_lemma int_formula_prop_eq_lemma int_term_value_var_lemma int_formula_prop_less_lemma int_formula_prop_le_lemma int_formula_prop_wf non_neg_length decidable__le length_wf_nat int_seg_properties nat_properties itermConstant_wf int_term_value_constant_lemma equal_wf true_wf select_l_index subtype_rel_self iff_weakening_equal
Rules used in proof :  sqequalSubstitution sqequalTransitivity computationStep sqequalReflexivity Error :isect_memberFormation_alt,  Error :lambdaFormation_alt,  cut introduction extract_by_obid sqequalHypSubstitution isectElimination thin productElimination equalityTransitivity hypothesis equalitySymmetry independent_isectElimination rename dependent_functionElimination because_Cache unionElimination hypothesisEquality applyEquality Error :lambdaEquality_alt,  setElimination Error :inhabitedIsType,  sqequalRule Error :universeIsType,  instantiate universeEquality Error :inlFormation_alt,  independent_functionElimination Error :equalityIstype,  Error :inrFormation_alt,  imageElimination productEquality natural_numberEquality approximateComputation Error :dependent_pairFormation_alt,  int_eqEquality Error :isect_memberEquality_alt,  voidElimination independent_pairFormation applyLambdaEquality imageMemberEquality baseClosed

Latex:
\mforall{}[T:Type]
    \mforall{}dT:EqDecider(T).  \mforall{}L:T  List.  \mforall{}x,y:T.
        ((x  \mmember{}  L)  {}\mRightarrow{}  (y  \mmember{}  L)  {}\mRightarrow{}  x  before  y  \mmember{}  L  \mvee{}  (x  =  y)  supposing  index(L;x)  \mleq{}  index(L;y))



Date html generated: 2019_06_20-PM-01_56_56
Last ObjectModification: 2019_01_13-PM-02_23_43

Theory : decidable!equality


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