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: List uimplies: supposing a uall: [x:A]. B[x] not: ¬A universe: Type equal: t ∈ T
Definitions unfolded in proof :  l_member: (x ∈ l) uall: [x:A]. B[x] member: t ∈ T uimplies: supposing a not: ¬A implies:  Q false: False exists: x:A. B[x] cand: c∧ B prop: so_lambda: λ2x.t[x] nat: ge: i ≥  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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