Nuprl Lemma : first_index_property
∀[T:Type]. ∀[P:T ⟶ 𝔹]. ∀[L:T List].
  (↑P[L[index-of-first x in L.P[x] - 1]]) ∧ (¬(∃x∈firstn(index-of-first x in L.P[x] - 1;L). ↑P[x])) 
  supposing 0 < index-of-first x in L.P[x]
Proof
Definitions occuring in Statement : 
first_index: index-of-first x in L.P[x]
, 
firstn: firstn(n;as)
, 
l_exists: (∃x∈L. P[x])
, 
select: L[n]
, 
list: T List
, 
assert: ↑b
, 
bool: 𝔹
, 
less_than: a < b
, 
uimplies: b supposing a
, 
uall: ∀[x:A]. B[x]
, 
so_apply: x[s]
, 
not: ¬A
, 
and: P ∧ Q
, 
function: x:A ⟶ B[x]
, 
subtract: n - m
, 
natural_number: $n
, 
universe: Type
Definitions unfolded in proof : 
all: ∀x:A. B[x]
, 
member: t ∈ T
, 
uall: ∀[x:A]. B[x]
, 
so_apply: x[s]
, 
int_seg: {i..j-}
, 
uimplies: b supposing a
, 
guard: {T}
, 
lelt: i ≤ j < k
, 
and: P ∧ Q
, 
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
, 
prop: ℙ
, 
less_than: a < b
, 
squash: ↓T
, 
first_index: index-of-first x in L.P[x]
, 
iff: P 
⇐⇒ Q
, 
cand: A c∧ B
, 
so_lambda: λ2x.t[x]
, 
subtype_rel: A ⊆r B
, 
ge: i ≥ j 
, 
rev_implies: P 
⇐ Q
, 
le: A ≤ B
, 
nat: ℕ
Lemmas referenced : 
btrue_neq_bfalse, 
assert_elim, 
equal_wf, 
and_wf, 
not_assert_elim, 
member-firstn, 
l_exists_iff, 
assert_witness, 
bool_wf, 
list_wf, 
less_than_wf, 
l_member_wf, 
assert_wf, 
firstn_wf, 
l_exists_wf, 
int_term_value_add_lemma, 
itermAdd_wf, 
lelt_wf, 
nat_wf, 
le_wf, 
nat_properties, 
search_wf, 
non_neg_length, 
int_term_value_subtract_lemma, 
itermSubtract_wf, 
first_index_wf, 
subtract_wf, 
int_seg_wf, 
int_formula_prop_less_lemma, 
intformless_wf, 
decidable__lt, 
int_formula_prop_wf, 
int_term_value_var_lemma, 
int_term_value_constant_lemma, 
int_formula_prop_le_lemma, 
int_formula_prop_not_lemma, 
int_formula_prop_and_lemma, 
itermVar_wf, 
itermConstant_wf, 
intformle_wf, 
intformnot_wf, 
intformand_wf, 
satisfiable-full-omega-tt, 
decidable__le, 
length_wf, 
int_seg_properties, 
select_wf, 
length_wf_nat, 
search_property
Rules used in proof : 
cut, 
lemma_by_obid, 
sqequalHypSubstitution, 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
dependent_functionElimination, 
thin, 
isectElimination, 
hypothesisEquality, 
hypothesis, 
lambdaEquality, 
applyEquality, 
cumulativity, 
setElimination, 
rename, 
independent_isectElimination, 
natural_numberEquality, 
productElimination, 
unionElimination, 
dependent_pairFormation, 
int_eqEquality, 
intEquality, 
isect_memberEquality, 
voidElimination, 
voidEquality, 
sqequalRule, 
independent_pairFormation, 
computeAll, 
because_Cache, 
imageElimination, 
equalityTransitivity, 
equalitySymmetry, 
setEquality, 
addEquality, 
introduction, 
functionEquality, 
universeEquality, 
isect_memberFormation, 
independent_pairEquality, 
independent_functionElimination, 
lambdaFormation, 
dependent_set_memberEquality
Latex:
\mforall{}[T:Type].  \mforall{}[P:T  {}\mrightarrow{}  \mBbbB{}].  \mforall{}[L:T  List].
    (\muparrow{}P[L[index-of-first  x  in  L.P[x]  -  1]])  \mwedge{}  (\mneg{}(\mexists{}x\mmember{}firstn(index-of-first  x  in  L.P[x]  -  1;L).  \muparrow{}P[x])) 
    supposing  0  <  index-of-first  x  in  L.P[x]
Date html generated:
2016_05_15-PM-04_11_58
Last ObjectModification:
2016_01_16-AM-11_09_00
Theory : general
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