Nuprl Lemma : fseg_select
∀[T:Type]
  ∀l1,l2:T List.
    (fseg(T;l1;l2) ⇐⇒ (||l1|| ≤ ||l2||) c∧ (∀i:ℕ. l1[i] = l2[(||l2|| - ||l1||) + i] ∈ T supposing i < ||l1||))
Proof
Definitions occuring in Statement : 
fseg: fseg(T;L1;L2), 
select: L[n], 
length: ||as||, 
list: T List, 
nat: ℕ, 
less_than: a < b, 
uimplies: b supposing a, 
uall: ∀[x:A]. B[x], 
cand: A c∧ B, 
le: A ≤ B, 
all: ∀x:A. B[x], 
iff: P ⇐⇒ Q, 
subtract: n - m, 
add: n + m, 
universe: Type, 
equal: s = t ∈ T
Definitions unfolded in proof : 
uall: ∀[x:A]. B[x], 
all: ∀x:A. B[x], 
iff: P ⇐⇒ Q, 
and: P ∧ Q, 
implies: P ⇒ Q, 
cand: A c∧ B, 
member: t ∈ T, 
uimplies: b supposing a, 
le: A ≤ B, 
nat: ℕ, 
prop: ℙ, 
rev_implies: P ⇐ Q, 
ge: i ≥ j , 
decidable: Dec(P), 
or: P ∨ Q, 
not: ¬A, 
satisfiable_int_formula: satisfiable_int_formula(fmla), 
exists: ∃x:A. B[x], 
false: False, 
less_than: a < b, 
squash: ↓T, 
fseg: fseg(T;L1;L2), 
subtype_rel: A ⊆r B, 
true: True, 
guard: {T}, 
uiff: uiff(P;Q), 
int_seg: {i..j-}, 
lelt: i ≤ j < k, 
int_iseg: {i...j}
Lemmas referenced : 
fseg_length, 
le_witness_for_triv, 
istype-less_than, 
length_wf, 
istype-nat, 
fseg_wf, 
istype-le, 
select_wf, 
nat_properties, 
decidable__le, 
full-omega-unsat, 
intformand_wf, 
intformnot_wf, 
intformle_wf, 
itermConstant_wf, 
itermVar_wf, 
istype-int, 
int_formula_prop_and_lemma, 
int_formula_prop_not_lemma, 
int_formula_prop_le_lemma, 
int_term_value_constant_lemma, 
int_term_value_var_lemma, 
int_formula_prop_wf, 
subtract_wf, 
itermAdd_wf, 
itermSubtract_wf, 
int_term_value_add_lemma, 
int_term_value_subtract_lemma, 
decidable__lt, 
intformless_wf, 
int_formula_prop_less_lemma, 
equal_wf, 
add_nat_wf, 
subtract_nat_wf, 
append_wf, 
le_wf, 
squash_wf, 
true_wf, 
length_append, 
subtype_rel_list, 
top_wf, 
subtype_rel_self, 
iff_weakening_equal, 
non_neg_length, 
length-append, 
add-is-int-iff, 
subtract-is-int-iff, 
intformeq_wf, 
int_formula_prop_eq_lemma, 
false_wf, 
istype-universe, 
select_append_back, 
add_functionality_wrt_eq, 
less_than_wf, 
list_wf, 
decidable__equal_int, 
firstn_wf, 
list_extensionality, 
nth_tl_wf, 
length_nth_tl, 
select-nth_tl, 
append_firstn_lastn
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
isect_memberFormation_alt, 
lambdaFormation_alt, 
independent_pairFormation, 
introduction, 
cut, 
extract_by_obid, 
sqequalHypSubstitution, 
isectElimination, 
thin, 
hypothesisEquality, 
independent_isectElimination, 
hypothesis, 
productElimination, 
equalityTransitivity, 
equalitySymmetry, 
setElimination, 
rename, 
universeIsType, 
sqequalRule, 
productIsType, 
functionIsType, 
isectIsType, 
because_Cache, 
equalityIstype, 
dependent_functionElimination, 
natural_numberEquality, 
unionElimination, 
approximateComputation, 
independent_functionElimination, 
dependent_pairFormation_alt, 
lambdaEquality_alt, 
int_eqEquality, 
Error :memTop, 
voidElimination, 
addEquality, 
imageElimination, 
dependent_set_memberEquality_alt, 
inhabitedIsType, 
hyp_replacement, 
applyLambdaEquality, 
applyEquality, 
imageMemberEquality, 
baseClosed, 
instantiate, 
universeEquality, 
pointwiseFunctionality, 
promote_hyp, 
baseApply, 
closedConclusion, 
productEquality, 
intEquality
Latex:
\mforall{}[T:Type]
    \mforall{}l1,l2:T  List.
        (fseg(T;l1;l2)
        \mLeftarrow{}{}\mRightarrow{}  (||l1||  \mleq{}  ||l2||)  c\mwedge{}  (\mforall{}i:\mBbbN{}.  l1[i]  =  l2[(||l2||  -  ||l1||)  +  i]  supposing  i  <  ||l1||))
Date html generated:
2020_05_20-AM-08_06_18
Last ObjectModification:
2019_12_31-PM-05_00_01
Theory : general
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