Nuprl Lemma : split_tail_max
∀[A:Type]
  ∀f:A ⟶ 𝔹. ∀L:A List. ∀a:A.
    ((a ∈ L) 
⇒ ((a ∈ snd(split_tail(L | ∀x.f[x])))) supposing ((∀b:A. (a before b ∈ L 
⇒ (↑f[b]))) and (↑f[a])))
Proof
Definitions occuring in Statement : 
split_tail: split_tail(L | ∀x.f[x])
, 
l_before: x before y ∈ l
, 
l_member: (x ∈ l)
, 
list: T List
, 
assert: ↑b
, 
bool: 𝔹
, 
uimplies: b supposing a
, 
uall: ∀[x:A]. B[x]
, 
so_apply: x[s]
, 
pi2: snd(t)
, 
all: ∀x:A. B[x]
, 
implies: P 
⇒ Q
, 
function: x:A ⟶ B[x]
, 
universe: Type
Definitions unfolded in proof : 
uall: ∀[x:A]. B[x]
, 
all: ∀x:A. B[x]
, 
member: t ∈ T
, 
so_lambda: λ2x.t[x]
, 
implies: P 
⇒ Q
, 
prop: ℙ
, 
uimplies: b supposing a
, 
so_apply: x[s]
, 
split_tail: split_tail(L | ∀x.f[x])
, 
so_lambda: so_lambda(x,y,z.t[x; y; z])
, 
top: Top
, 
so_apply: x[s1;s2;s3]
, 
pi2: snd(t)
, 
l_member: (x ∈ l)
, 
select: L[n]
, 
nil: []
, 
it: ⋅
, 
so_lambda: λ2x y.t[x; y]
, 
so_apply: x[s1;s2]
, 
cand: A c∧ B
, 
nat: ℕ
, 
iff: P 
⇐⇒ Q
, 
and: P ∧ Q
, 
or: P ∨ Q
, 
rev_implies: P 
⇐ Q
, 
not: ¬A
, 
false: False
, 
bool: 𝔹
, 
unit: Unit
, 
btrue: tt
, 
uiff: uiff(P;Q)
, 
ifthenelse: if b then t else f fi 
, 
bfalse: ff
, 
guard: {T}
Lemmas referenced : 
list_induction, 
all_wf, 
l_member_wf, 
isect_wf, 
assert_wf, 
l_before_wf, 
split_tail_wf, 
list_wf, 
pi2_wf, 
equal_wf, 
list_ind_nil_lemma, 
list_ind_cons_lemma, 
bool_wf, 
length_of_nil_lemma, 
stuck-spread, 
base_wf, 
assert_witness, 
nil_wf, 
exists_wf, 
nat_wf, 
less_than_wf, 
equal-wf-T-base, 
cons_wf, 
cons_member, 
split_tail_trivial, 
cons_before, 
bnot_wf, 
not_wf, 
assert_elim, 
not_assert_elim, 
and_wf, 
btrue_neq_bfalse, 
eqtt_to_assert, 
uiff_transitivity, 
eqff_to_assert, 
assert_of_bnot, 
list_ind_wf, 
ifthenelse_wf
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
isect_memberFormation_alt, 
lambdaFormation, 
cut, 
thin, 
introduction, 
extract_by_obid, 
sqequalHypSubstitution, 
isectElimination, 
hypothesisEquality, 
sqequalRule, 
lambdaEquality, 
functionEquality, 
hypothesis, 
applyEquality, 
productEquality, 
equalityTransitivity, 
equalitySymmetry, 
dependent_functionElimination, 
independent_functionElimination, 
isect_memberEquality, 
voidElimination, 
voidEquality, 
rename, 
because_Cache, 
universeIsType, 
universeEquality, 
baseClosed, 
independent_isectElimination, 
functionIsType, 
inhabitedIsType, 
setElimination, 
natural_numberEquality, 
productElimination, 
unionElimination, 
hyp_replacement, 
applyLambdaEquality, 
inlFormation, 
independent_pairFormation, 
dependent_set_memberEquality, 
equalityElimination, 
spreadEquality, 
dependent_pairEquality, 
inrFormation, 
independent_pairEquality
Latex:
\mforall{}[A:Type]
    \mforall{}f:A  {}\mrightarrow{}  \mBbbB{}.  \mforall{}L:A  List.  \mforall{}a:A.
        ((a  \mmember{}  L)
        {}\mRightarrow{}  ((a  \mmember{}  snd(split\_tail(L  |  \mforall{}x.f[x]))))  supposing 
                    ((\mforall{}b:A.  (a  before  b  \mmember{}  L  {}\mRightarrow{}  (\muparrow{}f[b])))  and 
                    (\muparrow{}f[a])))
Date html generated:
2019_10_15-AM-10_54_46
Last ObjectModification:
2018_09_27-AM-10_18_51
Theory : list!
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