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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