Nuprl Lemma : index-split_property
∀[T:Type]
  ∀L:T List. ∀idxs:ℕ List.
    let L1 = fst(index-split(L;idxs)) in
        ∃f:ℕ||L1|| ⟶ {i:ℕ||L||| (i ∈ idxs)} . (Bij(ℕ||L1||;{i:ℕ||L||| (i ∈ idxs)} f) ∧ (∀j:ℕ||L1||. (L1[j] = L[f j] ∈ \000CT)))
Proof
Definitions occuring in Statement : 
index-split: index-split(L;idxs)
, 
l_member: (x ∈ l)
, 
select: L[n]
, 
length: ||as||
, 
list: T List
, 
biject: Bij(A;B;f)
, 
int_seg: {i..j-}
, 
nat: ℕ
, 
let: let, 
uall: ∀[x:A]. B[x]
, 
pi1: fst(t)
, 
all: ∀x:A. B[x]
, 
exists: ∃x:A. B[x]
, 
and: P ∧ Q
, 
set: {x:A| B[x]} 
, 
apply: f a
, 
function: x:A ⟶ B[x]
, 
natural_number: $n
, 
int: ℤ
, 
universe: Type
, 
equal: s = t ∈ T
Definitions unfolded in proof : 
uall: ∀[x:A]. B[x]
, 
all: ∀x:A. B[x]
, 
member: t ∈ T
, 
uimplies: b supposing a
, 
sq_type: SQType(T)
, 
implies: P 
⇒ Q
, 
guard: {T}
, 
int_seg: {i..j-}
, 
subtype_rel: A ⊆r B
, 
nat: ℕ
, 
index-split: index-split(L;idxs)
, 
let: let, 
pi1: fst(t)
, 
prop: ℙ
, 
so_lambda: λ2x.t[x]
, 
so_apply: x[s]
, 
iff: P 
⇐⇒ Q
, 
and: P ∧ Q
, 
int_iseg: {i...j}
, 
cand: A c∧ B
, 
ge: i ≥ j 
, 
decidable: Dec(P)
, 
or: P ∨ Q
, 
false: False
, 
le: A ≤ B
, 
not: ¬A
, 
satisfiable_int_formula: satisfiable_int_formula(fmla)
, 
exists: ∃x:A. B[x]
, 
top: Top
, 
lelt: i ≤ j < k
, 
less_than: a < b
, 
squash: ↓T
, 
true: True
, 
rev_implies: P 
⇐ Q
, 
less_than': less_than'(a;b)
, 
biject: Bij(A;B;f)
, 
uiff: uiff(P;Q)
, 
no_repeats: no_repeats(T;l)
, 
surject: Surj(A;B;f)
, 
sq_stable: SqStable(P)
, 
l_member: (x ∈ l)
, 
permute-to-front: permute-to-front(L;idxs)
Lemmas referenced : 
permute-to-front-permutation, 
permutation-length, 
permute-to-front_wf, 
subtype_base_sq, 
int_subtype_base, 
length_upto, 
length_wf_nat, 
length-filter, 
int_seg_wf, 
length_wf, 
int-list-member_wf, 
subtype_rel_list, 
nat_wf, 
istype-nat, 
upto_wf, 
list_wf, 
istype-universe, 
filter_type, 
assert_wf, 
l_member_wf, 
subtype_rel_sets_simple, 
assert-int-list-member, 
istype-assert, 
list_subtype_base, 
set_subtype_base, 
lelt_wf, 
non_neg_length, 
decidable__le, 
full-omega-unsat, 
intformand_wf, 
intformnot_wf, 
intformle_wf, 
itermConstant_wf, 
itermVar_wf, 
istype-int, 
int_formula_prop_and_lemma, 
istype-void, 
int_formula_prop_not_lemma, 
int_formula_prop_le_lemma, 
int_term_value_constant_lemma, 
int_term_value_var_lemma, 
int_formula_prop_wf, 
istype-le, 
length_firstn, 
select_wf, 
int_seg_properties, 
decidable__lt, 
intformless_wf, 
int_formula_prop_less_lemma, 
biject_wf, 
firstn_wf, 
less_than_wf, 
length_firstn_eq, 
iff_weakening_equal, 
zero-le-nat, 
subtype_rel_set, 
int_seg_subtype_nat, 
istype-false, 
no_repeats_inject, 
no_repeats_upto, 
no_repeats_filter, 
istype-less_than, 
le_wf, 
decidable__equal_int_seg, 
decidable__equal_set, 
sq_stable__l_member, 
member_filter, 
member_upto, 
int_formula_prop_eq_lemma, 
intformeq_wf, 
decidable__equal_int, 
nat_properties, 
equal_wf, 
squash_wf, 
true_wf, 
select_firstn, 
subtype_rel_self, 
permute_list_select, 
append_wf, 
filter_wf5, 
bnot_wf, 
length-append, 
filter-split-length, 
select_append_front
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
isect_memberFormation_alt, 
lambdaFormation_alt, 
cut, 
introduction, 
extract_by_obid, 
sqequalHypSubstitution, 
isectElimination, 
thin, 
hypothesisEquality, 
dependent_functionElimination, 
because_Cache, 
hypothesis, 
independent_isectElimination, 
instantiate, 
cumulativity, 
intEquality, 
equalityTransitivity, 
equalitySymmetry, 
independent_functionElimination, 
sqequalRule, 
natural_numberEquality, 
lambdaEquality_alt, 
setElimination, 
rename, 
applyEquality, 
universeIsType, 
universeEquality, 
setEquality, 
productElimination, 
inhabitedIsType, 
equalityIstype, 
setIsType, 
dependent_set_memberEquality_alt, 
unionElimination, 
approximateComputation, 
dependent_pairFormation_alt, 
int_eqEquality, 
isect_memberEquality_alt, 
voidElimination, 
independent_pairFormation, 
productIsType, 
closedConclusion, 
imageElimination, 
functionIsType, 
imageMemberEquality, 
baseClosed, 
isectIsTypeImplies, 
functionIsTypeImplies, 
sqequalBase, 
baseApply, 
applyLambdaEquality, 
promote_hyp
Latex:
\mforall{}[T:Type]
    \mforall{}L:T  List.  \mforall{}idxs:\mBbbN{}  List.
        let  L1  =  fst(index-split(L;idxs))  in
                \mexists{}f:\mBbbN{}||L1||  {}\mrightarrow{}  \{i:\mBbbN{}||L|||  (i  \mmember{}  idxs)\}  .  (Bij(\mBbbN{}||L1||;\{i:\mBbbN{}||L|||  (i  \mmember{}  idxs)\}  ;f)  \mwedge{}  (\mforall{}j:\mBbbN{}||L1||\000C.  (L1[j]  =  L[f  j])))
Date html generated:
2019_10_15-AM-11_13_01
Last ObjectModification:
2019_06_25-PM-01_22_43
Theory : general
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