Nuprl Lemma : no_repeats-l_member!
∀[T:Type]. ∀l:T List. ∀x:T. ((x ∈ l) 
⇐⇒ (x ∈! l)) supposing no_repeats(T;l)
Proof
Definitions occuring in Statement : 
l_member!: (x ∈! l)
, 
no_repeats: no_repeats(T;l)
, 
l_member: (x ∈ l)
, 
list: T List
, 
uimplies: b supposing a
, 
uall: ∀[x:A]. B[x]
, 
all: ∀x:A. B[x]
, 
iff: P 
⇐⇒ Q
, 
universe: Type
Definitions unfolded in proof : 
uall: ∀[x:A]. B[x]
, 
all: ∀x:A. B[x]
, 
uimplies: b supposing a
, 
member: t ∈ T
, 
implies: P 
⇒ Q
, 
iff: P 
⇐⇒ Q
, 
and: P ∧ Q
, 
l_member: (x ∈ l)
, 
exists: ∃x:A. B[x]
, 
cand: A c∧ B
, 
l_member!: (x ∈! l)
, 
nat: ℕ
, 
no_repeats: no_repeats(T;l)
, 
decidable: Dec(P)
, 
or: P ∨ Q
, 
not: ¬A
, 
squash: ↓T
, 
guard: {T}
, 
false: False
, 
satisfiable_int_formula: satisfiable_int_formula(fmla)
, 
top: Top
, 
prop: ℙ
, 
subtype_rel: A ⊆r B
, 
so_lambda: λ2x.t[x]
, 
so_apply: x[s]
, 
sq_stable: SqStable(P)
, 
ge: i ≥ j 
, 
rev_implies: P 
⇐ Q
Lemmas referenced : 
no_repeats_witness, 
decidable__equal_int, 
satisfiable-full-omega-tt, 
intformand_wf, 
intformeq_wf, 
itermVar_wf, 
intformnot_wf, 
int_formula_prop_and_lemma, 
int_formula_prop_eq_lemma, 
int_term_value_var_lemma, 
int_formula_prop_not_lemma, 
int_formula_prop_wf, 
equal-wf-base, 
set_subtype_base, 
le_wf, 
int_subtype_base, 
sq_stable__le, 
decidable__le, 
intformle_wf, 
itermConstant_wf, 
int_formula_prop_le_lemma, 
int_term_value_constant_lemma, 
equal_wf, 
select_wf, 
nat_properties, 
less_than_wf, 
length_wf, 
nat_wf, 
all_wf, 
l_member_wf, 
l_member!_wf, 
no_repeats_wf, 
list_wf
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
isect_memberFormation, 
lambdaFormation, 
cut, 
introduction, 
extract_by_obid, 
sqequalHypSubstitution, 
isectElimination, 
thin, 
hypothesisEquality, 
independent_functionElimination, 
hypothesis, 
rename, 
independent_pairFormation, 
productElimination, 
dependent_pairFormation, 
dependent_set_memberEquality, 
dependent_functionElimination, 
setElimination, 
because_Cache, 
unionElimination, 
independent_isectElimination, 
applyLambdaEquality, 
sqequalRule, 
imageMemberEquality, 
baseClosed, 
imageElimination, 
natural_numberEquality, 
lambdaEquality, 
int_eqEquality, 
intEquality, 
isect_memberEquality, 
voidElimination, 
voidEquality, 
computeAll, 
applyEquality, 
equalityTransitivity, 
equalitySymmetry, 
cumulativity, 
productEquality, 
functionEquality, 
universeEquality
Latex:
\mforall{}[T:Type].  \mforall{}l:T  List.  \mforall{}x:T.  ((x  \mmember{}  l)  \mLeftarrow{}{}\mRightarrow{}  (x  \mmember{}!  l))  supposing  no\_repeats(T;l)
Date html generated:
2017_04_17-AM-07_29_12
Last ObjectModification:
2017_02_27-PM-04_07_36
Theory : list_1
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