Nuprl Lemma : l_member_non_nil

∀[T:Type]. ∀[x:T]. ∀[L:T List].  ¬(L = [] ∈ (T List)) supposing (x ∈ L)


Proof




Definitions occuring in Statement :  l_member: (x ∈ l),  nil: [],  list: T List,  uimplies: b supposing a,  uall: ∀[x:A]. B[x],  not: ¬A,  universe: Type,  equal: s = t ∈ T
Definitions unfolded in proof :  l_member: (x ∈ l),  uall: ∀[x:A]. B[x],  member: t ∈ T,  uimplies: b supposing a,  not: ¬A,  implies: P ⇒ Q,  false: False,  exists: ∃x:A. B[x],  cand: A c∧ B,  prop: ℙ,  so_lambda: λ2x.t[x],  nat: ℕ,  ge: i ≥ j ,  all: ∀x:A. B[x],  decidable: Dec(P),  or: P ∨ Q,  satisfiable_int_formula: satisfiable_int_formula(fmla),  top: Top,  and: P ∧ Q,  so_apply: x[s]
Lemmas referenced :  equal-wf-T-base,  list_wf,  exists_wf,  nat_wf,  less_than_wf,  length_wf,  equal_wf,  select_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,  length_of_nil_lemma,  intformless_wf,  int_formula_prop_less_lemma
Rules used in proof :  sqequalSubstitution,  sqequalRule,  sqequalReflexivity,  sqequalTransitivity,  computationStep,  isect_memberFormation,  introduction,  cut,  lambdaFormation,  thin,  sqequalHypSubstitution,  productElimination,  extract_by_obid,  isectElimination,  cumulativity,  hypothesisEquality,  hypothesis,  baseClosed,  independent_functionElimination,  voidElimination,  lambdaEquality,  dependent_functionElimination,  because_Cache,  productEquality,  setElimination,  rename,  independent_isectElimination,  natural_numberEquality,  unionElimination,  dependent_pairFormation,  int_eqEquality,  intEquality,  isect_memberEquality,  voidEquality,  independent_pairFormation,  computeAll,  equalityTransitivity,  equalitySymmetry,  universeEquality,  hyp_replacement,  applyLambdaEquality

Latex:
\mforall{}[T:Type].  \mforall{}[x:T].  \mforall{}[L:T  List].    \mneg{}(L  =  [])  supposing  (x  \mmember{}  L)



Date html generated: 2017_04_14-AM-09_26_52
Last ObjectModification: 2017_02_27-PM-04_00_37

Theory : list_1


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