Nuprl Lemma : split_rel_last
∀[A:Type]
  ∀r:A ⟶ A ⟶ 𝔹. ∀L:A List.
    (∃L1,L2:A List
      (((L = (L1 @ L2) ∈ (A List)) ∧ (¬↑null(L2)) ∧ (∀b∈L2.↑r[b;last(L)]))
      ∧ ¬↑r[last(L1);last(L)] supposing ¬↑null(L1))) supposing 
       ((¬↑null(L)) and 
       (∀a:A. (↑r[a;a])))
Proof
Definitions occuring in Statement : 
l_all: (∀x∈L.P[x]), 
last: last(L), 
null: null(as), 
append: as @ bs, 
list: T List, 
assert: ↑b, 
bool: 𝔹, 
uimplies: b supposing a, 
uall: ∀[x:A]. B[x], 
so_apply: x[s1;s2], 
all: ∀x:A. B[x], 
exists: ∃x:A. B[x], 
not: ¬A, 
and: P ∧ Q, 
function: x:A ⟶ B[x], 
universe: Type, 
equal: s = t ∈ T
Definitions unfolded in proof : 
implies: P ⇒ Q, 
top: Top, 
and: P ∧ Q, 
prop: ℙ, 
so_apply: x[s], 
so_apply: x[s1;s2], 
uimplies: b supposing a, 
so_lambda: λ2x.t[x], 
member: t ∈ T, 
all: ∀x:A. B[x], 
uall: ∀[x:A]. B[x], 
assert: ↑b, 
ifthenelse: if b then t else f fi , 
btrue: tt, 
not: ¬A, 
false: False, 
true: True, 
decidable: Dec(P), 
or: P ∨ Q, 
exists: ∃x:A. B[x], 
cons: [a / b], 
bfalse: ff, 
guard: {T}, 
select: L[n], 
subtract: n - m, 
last: last(L), 
so_apply: x[s1;s2;s3], 
so_lambda: so_lambda(x,y,z.t[x; y; z]), 
rev_implies: P ⇐ Q, 
iff: P ⇐⇒ Q, 
it: ⋅, 
nil: [], 
list_ind: list_ind, 
append: as @ bs, 
cand: A c∧ B, 
uiff: uiff(P;Q), 
squash: ↓T, 
subtype_rel: A ⊆r B, 
sq_type: SQType(T)
Lemmas referenced : 
bool_wf, 
l_member_wf, 
last_wf, 
l_all_wf, 
length-append, 
length_wf, 
append_wf, 
equal_wf, 
list_wf, 
exists_wf, 
null_wf, 
not_wf, 
assert_wf, 
all_wf, 
isect_wf, 
list_induction, 
null_nil_lemma, 
assert_witness, 
true_wf, 
decidable__assert, 
cons_wf, 
product_subtype_list, 
null_cons_lemma, 
list-cases, 
null_wf2, 
not_assert_elim, 
btrue_wf, 
length_of_nil_lemma, 
length_of_cons_lemma, 
list_ind_nil_lemma, 
l_all_single, 
btrue_neq_bfalse, 
bfalse_wf, 
assert_elim, 
nil_wf, 
false_wf, 
assert_of_null, 
nat_wf, 
length_wf_nat, 
squash_wf, 
last_cons, 
subtype_rel_self, 
iff_weakening_equal, 
l_all_cons, 
top_wf, 
subtype_rel_list, 
last_cons2, 
and_wf, 
iff_weakening_uiff, 
equal-wf-T-base, 
iff_functionality_wrt_iff, 
iff_imp_equal_bool, 
bool_subtype_base, 
subtype_base_sq, 
list_ind_cons_lemma
Rules used in proof : 
universeEquality, 
universeIsType, 
functionEquality, 
dependent_functionElimination, 
because_Cache, 
independent_functionElimination, 
isectEquality, 
setEquality, 
independent_isectElimination, 
rename, 
setElimination, 
voidEquality, 
voidElimination, 
isect_memberEquality, 
applyLambdaEquality, 
productEquality, 
hypothesis, 
applyEquality, 
lambdaEquality, 
sqequalRule, 
hypothesisEquality, 
isectElimination, 
sqequalHypSubstitution, 
extract_by_obid, 
introduction, 
thin, 
cut, 
lambdaFormation, 
isect_memberFormation_alt, 
sqequalReflexivity, 
computationStep, 
sqequalTransitivity, 
sqequalSubstitution, 
natural_numberEquality, 
functionIsType, 
inhabitedIsType, 
unionElimination, 
productElimination, 
hypothesis_subsumption, 
promote_hyp, 
functionExtensionality, 
cumulativity, 
equalitySymmetry, 
equalityTransitivity, 
independent_pairFormation, 
dependent_pairFormation, 
hyp_replacement, 
dependent_set_memberEquality, 
imageElimination, 
imageMemberEquality, 
baseClosed, 
instantiate
Latex:
\mforall{}[A:Type]
    \mforall{}r:A  {}\mrightarrow{}  A  {}\mrightarrow{}  \mBbbB{}.  \mforall{}L:A  List.
        (\mexists{}L1,L2:A  List
            (((L  =  (L1  @  L2))  \mwedge{}  (\mneg{}\muparrow{}null(L2))  \mwedge{}  (\mforall{}b\mmember{}L2.\muparrow{}r[b;last(L)]))
            \mwedge{}  \mneg{}\muparrow{}r[last(L1);last(L)]  supposing  \mneg{}\muparrow{}null(L1)))  supposing 
              ((\mneg{}\muparrow{}null(L))  and 
              (\mforall{}a:A.  (\muparrow{}r[a;a])))
Date html generated:
2019_10_15-AM-10_54_33
Last ObjectModification:
2018_09_27-AM-10_47_46
Theory : list!
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