Nuprl Lemma : first_index_equal
∀[T:Type]. ∀[L1,L2:T List]. ∀[P,Q:T ⟶ 𝔹].
  index-of-first a in L1.P[a] ∧b Q[a] = index-of-first a in L2.P[a] ∧b Q[a] ∈ ℤ supposing L1 agree_on(T;a.↑P[a]) L2
Proof
Definitions occuring in Statement : 
agree_on: agree_on(T;x.P[x])
, 
first_index: index-of-first x in L.P[x]
, 
list: T List
, 
band: p ∧b q
, 
assert: ↑b
, 
bool: 𝔹
, 
uimplies: b supposing a
, 
uall: ∀[x:A]. B[x]
, 
infix_ap: x f y
, 
so_apply: x[s]
, 
function: x:A ⟶ B[x]
, 
int: ℤ
, 
universe: Type
, 
equal: s = t ∈ T
Definitions unfolded in proof : 
uall: ∀[x:A]. B[x]
, 
member: t ∈ T
, 
all: ∀x:A. B[x]
, 
nat: ℕ
, 
implies: P 
⇒ Q
, 
false: False
, 
ge: i ≥ j 
, 
uimplies: b supposing a
, 
not: ¬A
, 
satisfiable_int_formula: satisfiable_int_formula(fmla)
, 
exists: ∃x:A. B[x]
, 
top: Top
, 
and: P ∧ Q
, 
prop: ℙ
, 
guard: {T}
, 
or: P ∨ Q
, 
agree_on: agree_on(T;x.P[x])
, 
so_lambda: λ2x.t[x]
, 
so_apply: x[s]
, 
subtype_rel: A ⊆r B
, 
cand: A c∧ B
, 
int_seg: {i..j-}
, 
lelt: i ≤ j < k
, 
decidable: Dec(P)
, 
cons: [a / b]
, 
colength: colength(L)
, 
nil: []
, 
it: ⋅
, 
sq_type: SQType(T)
, 
so_lambda: λ2x y.t[x; y]
, 
so_apply: x[s1;s2]
, 
infix_ap: x f y
, 
select: L[n]
, 
le: A ≤ B
, 
less_than': less_than'(a;b)
, 
less_than: a < b
, 
squash: ↓T
, 
bool: 𝔹
, 
unit: Unit
, 
btrue: tt
, 
uiff: uiff(P;Q)
, 
band: p ∧b q
, 
ifthenelse: if b then t else f fi 
, 
bfalse: ff
, 
bnot: ¬bb
, 
assert: ↑b
, 
subtract: n - m
, 
rev_implies: P 
⇐ Q
, 
iff: P 
⇐⇒ Q
, 
true: True
, 
nat_plus: ℕ+
Lemmas referenced : 
nat_properties, 
full-omega-unsat, 
intformand_wf, 
intformle_wf, 
itermConstant_wf, 
itermVar_wf, 
intformless_wf, 
istype-int, 
int_formula_prop_and_lemma, 
istype-void, 
int_formula_prop_le_lemma, 
int_term_value_constant_lemma, 
int_term_value_var_lemma, 
int_formula_prop_less_lemma, 
int_formula_prop_wf, 
ge_wf, 
less_than_wf, 
intformeq_wf, 
int_formula_prop_eq_lemma, 
list-cases, 
first_index_wf, 
nil_wf, 
void_wf, 
infix_ap_wf, 
list_wf, 
equal_wf, 
length_wf, 
all_wf, 
int_seg_wf, 
or_wf, 
assert_wf, 
select_wf, 
subtype_rel_list, 
int_seg_properties, 
decidable__le, 
intformnot_wf, 
int_formula_prop_not_lemma, 
decidable__lt, 
istype-universe, 
bool_wf, 
product_subtype_list, 
colength-cons-not-zero, 
agree_on_wf, 
subtract-1-ge-0, 
subtype_base_sq, 
set_subtype_base, 
int_subtype_base, 
spread_cons_lemma, 
length_of_nil_lemma, 
length_of_cons_lemma, 
stuck-spread, 
istype-base, 
non_neg_length, 
decidable__equal_int, 
itermAdd_wf, 
int_term_value_add_lemma, 
cons_wf, 
colength_wf_list, 
le_wf, 
istype-false, 
subtract_wf, 
itermSubtract_wf, 
int_term_value_subtract_lemma, 
first_index_cons, 
eqtt_to_assert, 
eqff_to_assert, 
bool_cases_sqequal, 
bool_subtype_base, 
assert-bnot, 
bfalse_wf, 
nat_wf, 
add-is-int-iff, 
false_wf, 
add-member-int_seg2, 
add-associates, 
add-swap, 
add-commutes, 
zero-add, 
add-subtract-cancel, 
iff_weakening_uiff, 
assert_functionality_wrt_uiff, 
select_cons_tl, 
squash_wf, 
true_wf, 
subtype_rel_self, 
iff_weakening_equal, 
decidable__or, 
decidable__assert, 
add_nat_plus, 
length_wf_nat, 
nat_plus_properties, 
ifthenelse_wf, 
lt_int_wf, 
equal-wf-base, 
ite_rw_false, 
not_wf, 
assert_of_lt_int
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
isect_memberFormation_alt, 
introduction, 
cut, 
thin, 
lambdaFormation_alt, 
extract_by_obid, 
sqequalHypSubstitution, 
isectElimination, 
hypothesisEquality, 
hypothesis, 
setElimination, 
rename, 
intWeakElimination, 
natural_numberEquality, 
independent_isectElimination, 
approximateComputation, 
independent_functionElimination, 
dependent_pairFormation_alt, 
lambdaEquality_alt, 
int_eqEquality, 
dependent_functionElimination, 
isect_memberEquality_alt, 
voidElimination, 
sqequalRule, 
independent_pairFormation, 
universeIsType, 
axiomEquality, 
equalityTransitivity, 
equalitySymmetry, 
applyLambdaEquality, 
inhabitedIsType, 
functionIsTypeImplies, 
unionElimination, 
because_Cache, 
voidEquality, 
functionExtensionality, 
instantiate, 
applyEquality, 
cumulativity, 
universeEquality, 
productEquality, 
intEquality, 
functionEquality, 
productElimination, 
functionIsType, 
promote_hyp, 
hypothesis_subsumption, 
equalityIsType1, 
equalityIsType4, 
baseClosed, 
dependent_set_memberEquality_alt, 
imageElimination, 
baseApply, 
closedConclusion, 
equalityElimination, 
pointwiseFunctionality, 
unionIsType, 
addEquality, 
productIsType, 
inlFormation_alt, 
inrFormation_alt, 
imageMemberEquality, 
hyp_replacement, 
equalityIsType2
Latex:
\mforall{}[T:Type].  \mforall{}[L1,L2:T  List].  \mforall{}[P,Q:T  {}\mrightarrow{}  \mBbbB{}].
    index-of-first  a  in  L1.P[a]  \mwedge{}\msubb{}  Q[a]  =  index-of-first  a  in  L2.P[a]  \mwedge{}\msubb{}  Q[a] 
    supposing  L1  agree\_on(T;a.\muparrow{}P[a])  L2
Date html generated:
2019_10_15-AM-10_58_20
Last ObjectModification:
2018_10_09-AM-09_57_25
Theory : list!
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