Nuprl Lemma : nth_tl_nth_tl
∀[m,n:ℕ]. ∀[L:Top List].  (nth_tl(m;nth_tl(n;L)) ~ nth_tl(m + n;L))
Proof
Definitions occuring in Statement : 
nth_tl: nth_tl(n;as)
, 
list: T List
, 
nat: ℕ
, 
uall: ∀[x:A]. B[x]
, 
top: Top
, 
add: n + m
, 
sqequal: s ~ t
Definitions unfolded in proof : 
uall: ∀[x:A]. B[x]
, 
member: t ∈ T
, 
nat: ℕ
, 
implies: P 
⇒ Q
, 
false: False
, 
ge: i ≥ j 
, 
uimplies: b supposing a
, 
satisfiable_int_formula: satisfiable_int_formula(fmla)
, 
exists: ∃x:A. B[x]
, 
not: ¬A
, 
all: ∀x:A. B[x]
, 
top: Top
, 
and: P ∧ Q
, 
prop: ℙ
, 
nth_tl: nth_tl(n;as)
, 
le_int: i ≤z j
, 
lt_int: i <z j
, 
bnot: ¬bb
, 
ifthenelse: if b then t else f fi 
, 
bfalse: ff
, 
btrue: tt
, 
decidable: Dec(P)
, 
or: P ∨ Q
, 
subtype_rel: A ⊆r B
, 
bool: 𝔹
, 
unit: Unit
, 
it: ⋅
, 
uiff: uiff(P;Q)
, 
guard: {T}
Lemmas referenced : 
nat_properties, 
satisfiable-full-omega-tt, 
intformand_wf, 
intformle_wf, 
itermConstant_wf, 
itermVar_wf, 
intformless_wf, 
int_formula_prop_and_lemma, 
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, 
list_wf, 
top_wf, 
nat_wf, 
zero-add, 
decidable__le, 
subtract_wf, 
intformnot_wf, 
itermSubtract_wf, 
int_formula_prop_not_lemma, 
int_term_value_subtract_lemma, 
le_int_wf, 
bool_wf, 
equal-wf-base, 
int_subtype_base, 
assert_wf, 
le_wf, 
lt_int_wf, 
bnot_wf, 
equal-wf-T-base, 
itermAdd_wf, 
int_term_value_add_lemma, 
uiff_transitivity, 
eqtt_to_assert, 
assert_of_le_int, 
eqff_to_assert, 
assert_functionality_wrt_uiff, 
bnot_of_le_int, 
assert_of_lt_int, 
equal_wf, 
tl_wf, 
general_arith_equation1
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
isect_memberFormation, 
introduction, 
cut, 
extract_by_obid, 
sqequalHypSubstitution, 
isectElimination, 
thin, 
hypothesisEquality, 
hypothesis, 
setElimination, 
rename, 
intWeakElimination, 
lambdaFormation, 
natural_numberEquality, 
independent_isectElimination, 
dependent_pairFormation, 
lambdaEquality, 
int_eqEquality, 
intEquality, 
dependent_functionElimination, 
isect_memberEquality, 
voidElimination, 
voidEquality, 
sqequalRule, 
independent_pairFormation, 
computeAll, 
independent_functionElimination, 
sqequalAxiom, 
because_Cache, 
unionElimination, 
baseApply, 
closedConclusion, 
baseClosed, 
applyEquality, 
addEquality, 
equalityElimination, 
productElimination, 
equalityTransitivity, 
equalitySymmetry
Latex:
\mforall{}[m,n:\mBbbN{}].  \mforall{}[L:Top  List].    (nth\_tl(m;nth\_tl(n;L))  \msim{}  nth\_tl(m  +  n;L))
Date html generated:
2017_04_14-AM-09_26_08
Last ObjectModification:
2017_02_27-PM-04_00_18
Theory : list_1
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