Nuprl Lemma : no_repeats_cons
∀[T:Type]. ∀[l:T List]. ∀[x:T].  uiff(no_repeats(T;[x / l]);no_repeats(T;l) ∧ (¬(x ∈ l)))
Proof
Definitions occuring in Statement : 
no_repeats: no_repeats(T;l)
, 
l_member: (x ∈ l)
, 
cons: [a / b]
, 
list: T List
, 
uiff: uiff(P;Q)
, 
uall: ∀[x:A]. B[x]
, 
not: ¬A
, 
and: P ∧ Q
, 
universe: Type
Definitions unfolded in proof : 
no_repeats: no_repeats(T;l)
, 
all: ∀x:A. B[x]
, 
member: t ∈ T
, 
top: Top
, 
uall: ∀[x:A]. B[x]
, 
uiff: uiff(P;Q)
, 
and: P ∧ Q
, 
uimplies: b supposing a
, 
not: ¬A
, 
implies: P 
⇒ Q
, 
false: False
, 
nat: ℕ
, 
sq_stable: SqStable(P)
, 
squash: ↓T
, 
prop: ℙ
, 
true: True
, 
less_than': less_than'(a;b)
, 
le: A ≤ B
, 
subtype_rel: A ⊆r B
, 
subtract: n - m
, 
rev_implies: P 
⇐ Q
, 
iff: P 
⇐⇒ Q
, 
or: P ∨ Q
, 
decidable: Dec(P)
, 
guard: {T}
, 
l_member: (x ∈ l)
, 
exists: ∃x:A. B[x]
, 
cand: A c∧ B
, 
select: L[n]
, 
cons: [a / b]
, 
sq_type: SQType(T)
, 
label: ...$L... t
Lemmas referenced : 
length_of_cons_lemma, 
istype-void, 
select_wf, 
sq_stable__le, 
not_wf, 
equal_wf, 
nat_wf, 
less_than_wf, 
length_wf, 
l_member_wf, 
cons_wf, 
list_wf, 
le_antisymmetry_iff, 
not-equal-2, 
decidable__equal_int, 
le-add-cancel2, 
less-iff-le, 
not-lt-2, 
decidable__lt, 
le_wf, 
le-add-cancel, 
add-zero, 
add_functionality_wrt_le, 
add-commutes, 
add-swap, 
add-associates, 
minus-one-mul-top, 
zero-add, 
minus-one-mul, 
minus-add, 
condition-implies-le, 
not-le-2, 
false_wf, 
decidable__le, 
squash_wf, 
true_wf, 
select_cons_tl, 
iff_weakening_equal, 
istype-false, 
istype-int, 
int_subtype_base, 
subtract_wf, 
minus-minus, 
subtype_rel_self, 
minus-zero, 
le-add-cancel-alt, 
subtype_base_sq
Rules used in proof : 
sqequalSubstitution, 
sqequalRule, 
sqequalReflexivity, 
sqequalTransitivity, 
computationStep, 
cut, 
introduction, 
extract_by_obid, 
sqequalHypSubstitution, 
dependent_functionElimination, 
thin, 
Error :isect_memberEquality_alt, 
voidElimination, 
hypothesis, 
Error :isect_memberFormation_alt, 
independent_pairFormation, 
Error :lambdaFormation_alt, 
independent_functionElimination, 
Error :equalityIsType1, 
Error :inhabitedIsType, 
hypothesisEquality, 
isectElimination, 
cumulativity, 
setElimination, 
rename, 
because_Cache, 
independent_isectElimination, 
natural_numberEquality, 
imageMemberEquality, 
baseClosed, 
imageElimination, 
Error :lambdaEquality_alt, 
Error :universeIsType, 
equalityTransitivity, 
equalitySymmetry, 
productElimination, 
independent_pairEquality, 
Error :isectIsType, 
addEquality, 
Error :productIsType, 
universeEquality, 
applyLambdaEquality, 
minusEquality, 
intEquality, 
voidEquality, 
isect_memberEquality, 
lambdaEquality, 
applyEquality, 
lambdaFormation, 
unionElimination, 
dependent_set_memberEquality, 
Error :dependent_set_memberEquality_alt, 
Error :equalityIsType4, 
instantiate, 
Error :dependent_pairFormation_alt, 
promote_hyp
Latex:
\mforall{}[T:Type].  \mforall{}[l:T  List].  \mforall{}[x:T].    uiff(no\_repeats(T;[x  /  l]);no\_repeats(T;l)  \mwedge{}  (\mneg{}(x  \mmember{}  l)))
Date html generated:
2019_06_20-PM-00_42_15
Last ObjectModification:
2018_10_01-PM-10_15_57
Theory : list_0
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