Nuprl Lemma : no_repeats_iff
∀[T:Type]. ∀[l:T List].  uiff(no_repeats(T;l);∀[x,y:T].  ¬(x = y ∈ T) supposing x before y ∈ l)
Proof
Definitions occuring in Statement : 
l_before: x before y ∈ l
, 
no_repeats: no_repeats(T;l)
, 
list: T List
, 
uiff: uiff(P;Q)
, 
uimplies: b supposing a
, 
uall: ∀[x:A]. B[x]
, 
not: ¬A
, 
universe: Type
, 
equal: s = t ∈ T
Definitions unfolded in proof : 
l_before: x before y ∈ l
, 
no_repeats: no_repeats(T;l)
, 
sublist: L1 ⊆ L2
, 
uall: ∀[x:A]. B[x]
, 
member: t ∈ T
, 
uiff: uiff(P;Q)
, 
and: P ∧ Q
, 
uimplies: b supposing a
, 
not: ¬A
, 
implies: P 
⇒ Q
, 
false: False
, 
exists: ∃x:A. B[x]
, 
int_seg: {i..j-}
, 
lelt: i ≤ j < k
, 
le: A ≤ B
, 
subtype_rel: A ⊆r B
, 
prop: ℙ
, 
all: ∀x:A. B[x]
, 
less_than: a < b
, 
squash: ↓T
, 
decidable: Dec(P)
, 
or: P ∨ Q
, 
satisfiable_int_formula: satisfiable_int_formula(fmla)
, 
ge: i ≥ j 
, 
nat: ℕ
, 
guard: {T}
, 
subtract: n - m
, 
cons: [a / b]
, 
select: L[n]
, 
true: True
, 
less_than': less_than'(a;b)
, 
top: Top
, 
rev_implies: P 
⇐ Q
, 
iff: P 
⇐⇒ Q
, 
increasing: increasing(f;k)
, 
cand: A c∧ B
, 
so_lambda: λ2x.t[x]
, 
so_apply: x[s]
, 
length: ||as||
, 
list_ind: list_ind, 
nil: []
, 
it: ⋅
, 
nequal: a ≠ b ∈ T 
, 
assert: ↑b
, 
bnot: ¬bb
, 
sq_type: SQType(T)
, 
bfalse: ff
, 
ifthenelse: if b then t else f fi 
, 
btrue: tt
, 
unit: Unit
, 
bool: 𝔹
, 
eq_int: (i =z j)
Lemmas referenced : 
int_seg_wf, 
length_wf, 
cons_wf, 
nil_wf, 
increasing_wf, 
length_wf_nat, 
select_wf, 
length_of_cons_lemma, 
length_of_nil_lemma, 
int_seg_properties, 
decidable__le, 
full-omega-unsat, 
intformand_wf, 
intformnot_wf, 
intformle_wf, 
itermConstant_wf, 
itermVar_wf, 
istype-int, 
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, 
decidable__lt, 
intformless_wf, 
itermAdd_wf, 
int_formula_prop_less_lemma, 
int_term_value_add_lemma, 
non_neg_length, 
istype-le, 
istype-less_than, 
nat_properties, 
istype-nat, 
istype-void, 
list_wf, 
istype-universe, 
lelt_wf, 
false_wf, 
iff_weakening_equal, 
equal_wf, 
true_wf, 
squash_wf, 
not_wf, 
satisfiable-full-omega-tt, 
int_seg_subtype_nat, 
nat_wf, 
int_formula_prop_eq_lemma, 
intformeq_wf, 
ifthenelse_wf, 
eq_int_wf, 
subtype_rel_dep_function, 
int_seg_subtype, 
istype-false, 
neg_assert_of_eq_int, 
assert-bnot, 
bool_subtype_base, 
subtype_base_sq, 
bool_cases_sqequal, 
eqff_to_assert, 
assert_of_eq_int, 
eqtt_to_assert, 
bool_wf, 
decidable__equal_int, 
int_subtype_base, 
int_seg_subtype_special, 
int_seg_cases, 
int_term_value_subtract_lemma, 
itermSubtract_wf, 
subtract_wf, 
select-cons-tl, 
select-cons-hd, 
equal-wf-base, 
le_wf
Rules used in proof : 
sqequalSubstitution, 
sqequalRule, 
sqequalReflexivity, 
sqequalTransitivity, 
computationStep, 
isect_memberFormation_alt, 
introduction, 
cut, 
independent_pairFormation, 
lambdaFormation_alt, 
thin, 
hypothesis, 
sqequalHypSubstitution, 
independent_functionElimination, 
voidElimination, 
equalityIstype, 
inhabitedIsType, 
hypothesisEquality, 
lambdaEquality_alt, 
dependent_functionElimination, 
because_Cache, 
functionIsTypeImplies, 
productIsType, 
functionIsType, 
universeIsType, 
extract_by_obid, 
isectElimination, 
natural_numberEquality, 
setElimination, 
rename, 
productElimination, 
functionExtensionality, 
applyEquality, 
equalityTransitivity, 
equalitySymmetry, 
independent_isectElimination, 
Error :memTop, 
imageElimination, 
unionElimination, 
approximateComputation, 
dependent_pairFormation_alt, 
int_eqEquality, 
addEquality, 
dependent_set_memberEquality_alt, 
applyLambdaEquality, 
isect_memberEquality_alt, 
isectIsTypeImplies, 
isectIsType, 
independent_pairEquality, 
instantiate, 
universeEquality, 
baseClosed, 
imageMemberEquality, 
lambdaFormation, 
dependent_set_memberEquality, 
voidEquality, 
isect_memberEquality, 
computeAll, 
intEquality, 
lambdaEquality, 
dependent_pairFormation, 
cumulativity, 
closedConclusion, 
promote_hyp, 
equalityElimination, 
hypothesis_subsumption
Latex:
\mforall{}[T:Type].  \mforall{}[l:T  List].    uiff(no\_repeats(T;l);\mforall{}[x,y:T].    \mneg{}(x  =  y)  supposing  x  before  y  \mmember{}  l)
Date html generated:
2020_05_19-PM-09_42_24
Last ObjectModification:
2020_01_04-PM-08_14_09
Theory : list_1
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