Nuprl Lemma : remove-repeats-fun-member
∀[A,B:Type].
  ∀eq:EqDecider(B). ∀f:A ⟶ B. ∀L:A List. ∀a:A.
    ((a ∈ remove-repeats-fun(eq;f;L)) 
⇐⇒ ∃i:ℕ||L||. ((L[i] = a ∈ A) ∧ (∀j:ℕi. (¬((f L[j]) = (f a) ∈ B)))))
Proof
Definitions occuring in Statement : 
remove-repeats-fun: remove-repeats-fun(eq;f;L)
, 
l_member: (x ∈ l)
, 
select: L[n]
, 
length: ||as||
, 
list: T List
, 
deq: EqDecider(T)
, 
int_seg: {i..j-}
, 
uall: ∀[x:A]. B[x]
, 
all: ∀x:A. B[x]
, 
exists: ∃x:A. B[x]
, 
iff: P 
⇐⇒ Q
, 
not: ¬A
, 
and: P ∧ Q
, 
apply: f a
, 
function: x:A ⟶ B[x]
, 
natural_number: $n
, 
universe: Type
, 
equal: s = t ∈ T
Definitions unfolded in proof : 
uall: ∀[x:A]. B[x]
, 
all: ∀x:A. B[x]
, 
member: t ∈ T
, 
so_lambda: λ2x.t[x]
, 
prop: ℙ
, 
and: P ∧ Q
, 
int_seg: {i..j-}
, 
uimplies: b supposing a
, 
guard: {T}
, 
lelt: i ≤ j < k
, 
decidable: Dec(P)
, 
or: P ∨ Q
, 
satisfiable_int_formula: satisfiable_int_formula(fmla)
, 
exists: ∃x:A. B[x]
, 
false: False
, 
implies: P 
⇒ Q
, 
not: ¬A
, 
top: Top
, 
less_than: a < b
, 
squash: ↓T
, 
so_apply: x[s]
, 
remove-repeats-fun: remove-repeats-fun(eq;f;L)
, 
so_lambda: so_lambda(x,y,z.t[x; y; z])
, 
so_apply: x[s1;s2;s3]
, 
select: L[n]
, 
nil: []
, 
it: ⋅
, 
so_lambda: λ2x y.t[x; y]
, 
so_apply: x[s1;s2]
, 
iff: P 
⇐⇒ Q
, 
rev_implies: P 
⇐ Q
, 
deq: EqDecider(T)
, 
le: A ≤ B
, 
less_than': less_than'(a;b)
, 
nat_plus: ℕ+
, 
true: True
, 
uiff: uiff(P;Q)
, 
cons: [a / b]
, 
cand: A c∧ B
, 
ge: i ≥ j 
, 
eqof: eqof(d)
, 
subtract: n - m
, 
subtype_rel: A ⊆r B
Lemmas referenced : 
list_induction, 
all_wf, 
iff_wf, 
l_member_wf, 
remove-repeats-fun_wf, 
exists_wf, 
int_seg_wf, 
length_wf, 
equal_wf, 
select_wf, 
int_seg_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, 
decidable__lt, 
intformless_wf, 
int_formula_prop_less_lemma, 
not_wf, 
list_wf, 
list_ind_nil_lemma, 
length_of_nil_lemma, 
stuck-spread, 
base_wf, 
null_nil_lemma, 
btrue_wf, 
member-implies-null-eq-bfalse, 
nil_wf, 
btrue_neq_bfalse, 
equal-wf-base-T, 
list_ind_cons_lemma, 
length_of_cons_lemma, 
cons_wf, 
filter_wf5, 
bnot_wf, 
deq_wf, 
cons_member, 
false_wf, 
add_nat_plus, 
length_wf_nat, 
less_than_wf, 
nat_plus_wf, 
nat_plus_properties, 
add-is-int-iff, 
itermAdd_wf, 
intformeq_wf, 
int_term_value_add_lemma, 
int_formula_prop_eq_lemma, 
lelt_wf, 
non_neg_length, 
member_filter_2, 
assert_wf, 
eqof_wf, 
iff_transitivity, 
iff_weakening_uiff, 
assert_of_bnot, 
safe-assert-deq, 
add-member-int_seg2, 
subtract_wf, 
itermSubtract_wf, 
int_term_value_subtract_lemma, 
select-cons-tl, 
add-subtract-cancel, 
decidable__equal_int, 
squash_wf, 
le_wf, 
iff_weakening_equal, 
select_cons_tl, 
true_wf, 
member_filter
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
isect_memberFormation, 
lambdaFormation, 
cut, 
thin, 
introduction, 
extract_by_obid, 
sqequalHypSubstitution, 
isectElimination, 
hypothesisEquality, 
sqequalRule, 
lambdaEquality, 
cumulativity, 
because_Cache, 
functionExtensionality, 
applyEquality, 
hypothesis, 
natural_numberEquality, 
productEquality, 
setElimination, 
rename, 
independent_isectElimination, 
productElimination, 
dependent_functionElimination, 
unionElimination, 
dependent_pairFormation, 
int_eqEquality, 
intEquality, 
isect_memberEquality, 
voidElimination, 
voidEquality, 
independent_pairFormation, 
computeAll, 
imageElimination, 
independent_functionElimination, 
baseClosed, 
equalityTransitivity, 
equalitySymmetry, 
setEquality, 
functionEquality, 
universeEquality, 
dependent_set_memberEquality, 
imageMemberEquality, 
applyLambdaEquality, 
pointwiseFunctionality, 
promote_hyp, 
baseApply, 
closedConclusion, 
addEquality, 
impliesFunctionality, 
inlFormation, 
inrFormation
Latex:
\mforall{}[A,B:Type].
    \mforall{}eq:EqDecider(B).  \mforall{}f:A  {}\mrightarrow{}  B.  \mforall{}L:A  List.  \mforall{}a:A.
        ((a  \mmember{}  remove-repeats-fun(eq;f;L))  \mLeftarrow{}{}\mRightarrow{}  \mexists{}i:\mBbbN{}||L||.  ((L[i]  =  a)  \mwedge{}  (\mforall{}j:\mBbbN{}i.  (\mneg{}((f  L[j])  =  (f  a))))))
Date html generated:
2017_04_17-AM-09_12_07
Last ObjectModification:
2017_02_27-PM-05_20_47
Theory : decidable!equality
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