Nuprl Lemma : list-at-combine-skips
∀[ms,ns:colist(ℕ)]. ∀[k:ℕ]. ∀[T:Type]. ∀[L:colist(T)].  (L@combine-skips(ns;ms;k) = nth_tl(k;L)@ns@ms ∈ colist(T))
Proof
Definitions occuring in Statement : 
combine-skips: combine-skips(as;bs;n)
, 
list-at: L1@L2
, 
nth_tl: nth_tl(n;as)
, 
colist: colist(T)
, 
nat: ℕ
, 
uall: ∀[x:A]. B[x]
, 
universe: Type
, 
equal: s = t ∈ T
Definitions unfolded in proof : 
uall: ∀[x:A]. B[x]
, 
member: t ∈ T
, 
colist: colist(T)
, 
corec: corec(T.F[T])
, 
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]
, 
all: ∀x:A. B[x]
, 
top: Top
, 
and: P ∧ Q
, 
prop: ℙ
, 
lt_int: i <z j
, 
subtract: n - m
, 
ifthenelse: if b then t else f fi 
, 
btrue: tt
, 
bool: 𝔹
, 
unit: Unit
, 
it: ⋅
, 
uiff: uiff(P;Q)
, 
bfalse: ff
, 
or: P ∨ Q
, 
sq_type: SQType(T)
, 
guard: {T}
, 
bnot: ¬bb
, 
assert: ↑b
, 
rev_implies: P 
⇐ Q
, 
iff: P 
⇐⇒ Q
, 
ext-eq: A ≡ B
, 
subtype_rel: A ⊆r B
, 
nil: []
, 
combine-skips: combine-skips(as;bs;n)
, 
b-union: A ⋃ B
, 
tunion: ⋃x:A.B[x]
, 
decidable: Dec(P)
, 
pi2: snd(t)
, 
cons: [a / b]
, 
list-at: L1@L2
, 
null: null(as)
, 
nth_tl: nth_tl(n;as)
, 
le_int: i ≤z j
, 
squash: ↓T
, 
true: True
, 
co-nil: ()
, 
so_lambda: λ2x.t[x]
, 
so_apply: x[s]
, 
tl: tl(l)
, 
co-cons: [x / L]
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, 
istype-less_than, 
primrec-unroll, 
colist_wf, 
istype-universe, 
istype-nat, 
nat_wf, 
subtract-1-ge-0, 
lt_int_wf, 
eqtt_to_assert, 
assert_of_lt_int, 
eqff_to_assert, 
bool_cases_sqequal, 
subtype_base_sq, 
bool_wf, 
bool_subtype_base, 
assert-bnot, 
iff_weakening_uiff, 
assert_wf, 
less_than_wf, 
colist-ext, 
isaxiom_wf_listunion, 
subtype_rel_b-union-left, 
unit_wf2, 
axiom-listunion, 
null_nil_lemma, 
reduce_tl_nil_lemma, 
list_at_nil2_lemma, 
btrue_wf, 
it_wf, 
ifthenelse_wf, 
primrec_wf, 
subtract_wf, 
decidable__le, 
intformnot_wf, 
itermSubtract_wf, 
int_formula_prop_not_lemma, 
int_term_value_subtract_lemma, 
istype-le, 
top_wf, 
b-union_wf, 
int_seg_wf, 
subtype_rel_b-union-right, 
non-axiom-listunion, 
null_cons_lemma, 
reduce_hd_cons_lemma, 
reduce_tl_cons_lemma, 
intformeq_wf, 
int_formula_prop_eq_lemma, 
int_subtype_base, 
add-zero, 
nth_tl_nil, 
bfalse_wf, 
equal_wf, 
squash_wf, 
true_wf, 
list-at_wf, 
subtype_rel_self, 
iff_weakening_equal, 
le_int_wf, 
assert_of_le_int, 
le_wf, 
co-nil_wf, 
itermAdd_wf, 
int_term_value_add_lemma, 
set_subtype_base, 
decidable__equal_int, 
nil-at, 
co-cons_wf, 
subtract-add-cancel
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
Error :isect_memberFormation_alt, 
introduction, 
cut, 
Error :isect_memberEquality_alt, 
thin, 
extract_by_obid, 
sqequalHypSubstitution, 
isectElimination, 
hypothesisEquality, 
hypothesis, 
setElimination, 
rename, 
intWeakElimination, 
Error :lambdaFormation_alt, 
natural_numberEquality, 
independent_isectElimination, 
approximateComputation, 
independent_functionElimination, 
Error :dependent_pairFormation_alt, 
Error :lambdaEquality_alt, 
int_eqEquality, 
dependent_functionElimination, 
voidElimination, 
sqequalRule, 
independent_pairFormation, 
Error :universeIsType, 
axiomEquality, 
Error :functionIsTypeImplies, 
Error :inhabitedIsType, 
because_Cache, 
instantiate, 
universeEquality, 
unionElimination, 
equalityElimination, 
equalityTransitivity, 
equalitySymmetry, 
productElimination, 
Error :equalityIstype, 
promote_hyp, 
cumulativity, 
hypothesis_subsumption, 
applyEquality, 
productEquality, 
imageMemberEquality, 
Error :dependent_pairEquality_alt, 
Error :dependent_set_memberEquality_alt, 
baseClosed, 
sqequalBase, 
int_eqReduceFalseSq, 
Error :isectIsTypeImplies, 
independent_pairEquality, 
imageElimination, 
Error :isectIsType, 
baseApply, 
closedConclusion, 
intEquality, 
axiomSqEquality, 
addEquality
Latex:
\mforall{}[ms,ns:colist(\mBbbN{})].  \mforall{}[k:\mBbbN{}].  \mforall{}[T:Type].  \mforall{}[L:colist(T)].
    (L@combine-skips(ns;ms;k)  =  nth\_tl(k;L)@ns@ms)
Date html generated:
2019_06_20-PM-01_21_43
Last ObjectModification:
2018_12_07-PM-06_27_53
Theory : list_1
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