Nuprl Lemma : append_split2
∀[T:Type]
  ∀L:T List
    ∀[P:ℕ||L|| ⟶ ℙ]
      ((∀x:ℕ||L||. Dec(P x))
      
⇒ (∀i,j:ℕ||L||.  ((P i) 
⇒ P j supposing i < j))
      
⇒ (∃L_1,L_2:T List. ((L = (L_1 @ L_2) ∈ (T List)) ∧ (∀i:ℕ||L||. (P i 
⇐⇒ ||L_1|| ≤ i)))))
Proof
Definitions occuring in Statement : 
length: ||as||
, 
append: as @ bs
, 
list: T List
, 
int_seg: {i..j-}
, 
less_than: a < b
, 
decidable: Dec(P)
, 
uimplies: b supposing a
, 
uall: ∀[x:A]. B[x]
, 
prop: ℙ
, 
le: A ≤ B
, 
all: ∀x:A. B[x]
, 
exists: ∃x:A. B[x]
, 
iff: P 
⇐⇒ Q
, 
implies: P 
⇒ Q
, 
and: P ∧ Q
, 
apply: f a
, 
function: x:A ⟶ B[x]
, 
natural_number: $n
, 
universe: Type
, 
equal: s = t ∈ T
Definitions unfolded in proof : 
member: t ∈ T
, 
uall: ∀[x:A]. B[x]
, 
prop: ℙ
, 
and: P ∧ Q
, 
subtype_rel: A ⊆r B
, 
int_seg: {i..j-}
, 
so_lambda: λ2x.t[x]
, 
lelt: i ≤ j < k
, 
guard: {T}
, 
all: ∀x:A. B[x]
, 
decidable: Dec(P)
, 
or: P ∨ Q
, 
less_than: a < b
, 
squash: ↓T
, 
uimplies: b supposing a
, 
satisfiable_int_formula: satisfiable_int_formula(fmla)
, 
exists: ∃x:A. B[x]
, 
false: False
, 
implies: P 
⇒ Q
, 
not: ¬A
, 
top: Top
, 
so_apply: x[s]
, 
cand: A c∧ B
, 
int_iseg: {i...j}
, 
true: True
, 
iff: P 
⇐⇒ Q
, 
rev_implies: P 
⇐ Q
, 
le: A ≤ B
, 
nat: ℕ
, 
less_than': less_than'(a;b)
, 
ge: i ≥ j 
, 
label: ...$L... t
Lemmas referenced : 
length_wf, 
all_wf, 
int_seg_wf, 
not_wf, 
int_seg_properties, 
decidable__lt, 
satisfiable-full-omega-tt, 
intformand_wf, 
intformnot_wf, 
intformless_wf, 
itermVar_wf, 
int_formula_prop_and_lemma, 
int_formula_prop_not_lemma, 
int_formula_prop_less_lemma, 
int_term_value_var_lemma, 
int_formula_prop_wf, 
lelt_wf, 
decidable__exists_int_seg, 
decidable__and2, 
decidable__all_int_seg, 
decidable__not, 
less_than_wf, 
decidable_wf, 
list_wf, 
firstn_wf, 
nth_tl_wf, 
equal_wf, 
squash_wf, 
true_wf, 
append_firstn_lastn, 
subtype_rel_sets, 
le_wf, 
decidable__le, 
intformle_wf, 
int_formula_prop_le_lemma, 
iff_weakening_equal, 
less_than'_wf, 
append_wf, 
length-append, 
length_firstn, 
exists_wf, 
iff_wf, 
decidable__equal_int, 
itermConstant_wf, 
intformeq_wf, 
int_term_value_constant_lemma, 
int_formula_prop_eq_lemma, 
nil_wf, 
append_back_nil, 
nat_wf, 
false_wf, 
subtract_wf, 
itermSubtract_wf, 
int_term_value_subtract_lemma, 
set_wf, 
primrec-wf2, 
nat_properties
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
natural_numberEquality, 
cut, 
introduction, 
extract_by_obid, 
sqequalHypSubstitution, 
isectElimination, 
thin, 
cumulativity, 
hypothesisEquality, 
hypothesis, 
lambdaEquality, 
productEquality, 
applyEquality, 
functionExtensionality, 
because_Cache, 
sqequalRule, 
setElimination, 
rename, 
dependent_set_memberEquality, 
productElimination, 
independent_pairFormation, 
dependent_functionElimination, 
unionElimination, 
imageElimination, 
independent_isectElimination, 
dependent_pairFormation, 
int_eqEquality, 
intEquality, 
isect_memberEquality, 
voidElimination, 
voidEquality, 
computeAll, 
isect_memberFormation, 
lambdaFormation, 
instantiate, 
independent_functionElimination, 
functionEquality, 
universeEquality, 
isectEquality, 
equalityTransitivity, 
equalitySymmetry, 
setEquality, 
applyLambdaEquality, 
imageMemberEquality, 
baseClosed, 
independent_pairEquality, 
axiomEquality, 
hyp_replacement, 
hypothesis_subsumption
Latex:
\mforall{}[T:Type]
    \mforall{}L:T  List
        \mforall{}[P:\mBbbN{}||L||  {}\mrightarrow{}  \mBbbP{}]
            ((\mforall{}x:\mBbbN{}||L||.  Dec(P  x))
            {}\mRightarrow{}  (\mforall{}i,j:\mBbbN{}||L||.    ((P  i)  {}\mRightarrow{}  P  j  supposing  i  <  j))
            {}\mRightarrow{}  (\mexists{}L$_{1}$,L$_{2}$:T  List.  ((L  =  (L$_{1\mbackslash{}\000Cff7d$  @  L$_{2}$))  \mwedge{}  (\mforall{}i:\mBbbN{}||L||.  (P  i  \mLeftarrow{}{}\mRightarrow{}  ||L$_{1}$||  \mleq{}  i\000C)))))
Date html generated:
2017_04_14-AM-09_25_30
Last ObjectModification:
2017_02_27-PM-04_00_30
Theory : list_1
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