Nuprl Lemma : remove-repeats-length-no-repeats
∀[T:Type]. ∀[eq:EqDecider(T)]. ∀[L:T List].  ||remove-repeats(eq;L)|| = ||L|| ∈ ℤ supposing no_repeats(T;L)
Proof
Definitions occuring in Statement : 
remove-repeats: remove-repeats(eq;L)
, 
no_repeats: no_repeats(T;l)
, 
length: ||as||
, 
list: T List
, 
deq: EqDecider(T)
, 
uimplies: b supposing a
, 
uall: ∀[x:A]. B[x]
, 
int: ℤ
, 
universe: Type
, 
equal: s = t ∈ T
Definitions unfolded in proof : 
uall: ∀[x:A]. B[x]
, 
member: t ∈ T
, 
so_lambda: λ2x.t[x]
, 
implies: P 
⇒ Q
, 
prop: ℙ
, 
so_apply: x[s]
, 
all: ∀x:A. B[x]
, 
uimplies: b supposing a
, 
top: Top
, 
uiff: uiff(P;Q)
, 
and: P ∧ Q
, 
append: as @ bs
, 
so_lambda: so_lambda(x,y,z.t[x; y; z])
, 
so_apply: x[s1;s2;s3]
, 
squash: ↓T
, 
true: True
, 
subtype_rel: A ⊆r B
, 
guard: {T}
, 
iff: P 
⇐⇒ Q
, 
rev_implies: P 
⇐ Q
, 
or: P ∨ Q
, 
not: ¬A
, 
false: False
, 
decidable: Dec(P)
, 
satisfiable_int_formula: satisfiable_int_formula(fmla)
, 
exists: ∃x:A. B[x]
Lemmas referenced : 
list_induction, 
no_repeats_wf, 
equal_wf, 
length_wf, 
remove-repeats_wf, 
list_wf, 
deq_wf, 
remove_repeats_nil_lemma, 
length_of_nil_lemma, 
nil_wf, 
no_repeats_cons, 
list_ind_cons_lemma, 
list_ind_nil_lemma, 
squash_wf, 
true_wf, 
remove-repeats-append, 
cons_wf, 
append_wf, 
iff_weakening_equal, 
remove-repeats-append-one-member, 
length-append, 
length_of_cons_lemma, 
decidable__equal_int, 
satisfiable-full-omega-tt, 
intformand_wf, 
intformnot_wf, 
intformeq_wf, 
itermVar_wf, 
itermAdd_wf, 
itermConstant_wf, 
int_formula_prop_and_lemma, 
int_formula_prop_not_lemma, 
int_formula_prop_eq_lemma, 
int_term_value_var_lemma, 
int_term_value_add_lemma, 
int_term_value_constant_lemma, 
int_formula_prop_wf
Rules used in proof : 
cut, 
thin, 
introduction, 
extract_by_obid, 
sqequalHypSubstitution, 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
isectElimination, 
hypothesisEquality, 
sqequalRule, 
lambdaEquality, 
functionEquality, 
cumulativity, 
hypothesis, 
intEquality, 
independent_functionElimination, 
lambdaFormation, 
rename, 
because_Cache, 
dependent_functionElimination, 
universeEquality, 
isect_memberFormation, 
isect_memberEquality, 
axiomEquality, 
equalityTransitivity, 
equalitySymmetry, 
voidElimination, 
voidEquality, 
natural_numberEquality, 
productElimination, 
independent_isectElimination, 
applyEquality, 
imageElimination, 
equalityUniverse, 
levelHypothesis, 
imageMemberEquality, 
baseClosed, 
unionElimination, 
dependent_pairFormation, 
int_eqEquality, 
independent_pairFormation, 
computeAll
Latex:
\mforall{}[T:Type].  \mforall{}[eq:EqDecider(T)].  \mforall{}[L:T  List].
    ||remove-repeats(eq;L)||  =  ||L||  supposing  no\_repeats(T;L)
Date html generated:
2017_04_17-AM-09_12_42
Last ObjectModification:
2017_02_27-PM-05_19_39
Theory : decidable!equality
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