Nuprl Lemma : l_member-alt-def

[T:Type]. ∀L:T List. ∀x:T.  ((x ∈ L) ⇐⇒ ∃i:ℕ||L||. (x L[i] ∈ T))


Proof




Definitions occuring in Statement :  l_member: (x ∈ l) select: L[n] length: ||as|| list: List int_seg: {i..j-} uall: [x:A]. B[x] all: x:A. B[x] exists: x:A. B[x] iff: ⇐⇒ Q natural_number: $n universe: Type equal: t ∈ T
Definitions unfolded in proof :  l_member: (x ∈ l) uall: [x:A]. B[x] all: x:A. B[x] iff: ⇐⇒ Q and: P ∧ Q implies:  Q exists: x:A. B[x] member: t ∈ T nat: int_seg: {i..j-} lelt: i ≤ j < k prop: cand: c∧ B uimplies: supposing a guard: {T} ge: i ≥  decidable: Dec(P) or: P ∨ Q satisfiable_int_formula: satisfiable_int_formula(fmla) false: False not: ¬A top: Top less_than: a < b squash: T so_lambda: λ2x.t[x] so_apply: x[s] rev_implies:  Q subtype_rel: A ⊆B le: A ≤ B less_than': less_than'(a;b)
Lemmas referenced :  lelt_wf equal_wf select_wf int_seg_properties length_wf nat_properties decidable__le satisfiable-full-omega-tt intformand_wf intformnot_wf intformle_wf itermConstant_wf itermVar_wf int_formula_prop_and_lemma int_formula_prop_not_lemma int_formula_prop_le_lemma int_term_value_constant_lemma int_term_value_var_lemma int_formula_prop_wf decidable__lt intformless_wf int_formula_prop_less_lemma exists_wf nat_wf less_than_wf int_seg_subtype_nat false_wf int_seg_wf list_wf
Rules used in proof :  sqequalSubstitution sqequalRule sqequalReflexivity sqequalTransitivity computationStep isect_memberFormation lambdaFormation independent_pairFormation sqequalHypSubstitution productElimination thin dependent_pairFormation setElimination rename dependent_set_memberEquality hypothesisEquality hypothesis cut introduction extract_by_obid isectElimination because_Cache addLevel levelHypothesis independent_isectElimination natural_numberEquality cumulativity dependent_functionElimination unionElimination lambdaEquality int_eqEquality intEquality isect_memberEquality voidElimination voidEquality computeAll imageElimination productEquality applyEquality universeEquality

Latex:
\mforall{}[T:Type].  \mforall{}L:T  List.  \mforall{}x:T.    ((x  \mmember{}  L)  \mLeftarrow{}{}\mRightarrow{}  \mexists{}i:\mBbbN{}||L||.  (x  =  L[i]))



Date html generated: 2017_04_17-AM-07_25_28
Last ObjectModification: 2017_02_27-PM-04_04_19

Theory : list_1


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