Nuprl Lemma : firstn-append
∀[L1,L2:Top List]. ∀[n:ℕ]. (firstn(n;L1 @ L2) ~ if n ≤z ||L1|| then firstn(n;L1) else L1 @ firstn(n - ||L1||;L2) fi )
Proof
Definitions occuring in Statement :
firstn: firstn(n;as),
length: ||as||,
append: as @ bs,
list: T List,
le_int: i ≤z j,
nat: ℕ,
ifthenelse: if b then t else f fi ,
uall: ∀[x:A]. B[x],
top: Top,
subtract: n - m,
sqequal: s ~ 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,
satisfiable_int_formula: satisfiable_int_formula(fmla),
exists: ∃x:A. B[x],
not: ¬A,
top: Top,
and: P ∧ Q,
prop: ℙ,
subtype_rel: A ⊆r B,
guard: {T},
or: P ∨ Q,
firstn: firstn(n;as),
append: as @ bs,
so_lambda: so_lambda(x,y,z.t[x; y; z]),
so_apply: x[s1;s2;s3],
cons: [a / b],
colength: colength(L),
so_lambda: λ2x y.t[x; y],
so_apply: x[s1;s2],
decidable: Dec(P),
nil: [],
it: ⋅,
so_lambda: λ2x.t[x],
so_apply: x[s],
sq_type: SQType(T),
less_than: a < b,
squash: ↓T,
less_than': less_than'(a;b),
bool: 𝔹,
unit: Unit,
btrue: tt,
uiff: uiff(P;Q),
ifthenelse: if b then t else f fi ,
bfalse: ff,
bnot: ¬bb,
assert: ↑b,
int_seg: {i..j-},
lelt: i ≤ j < k,
le: A ≤ B
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,
nat_wf,
list_wf,
top_wf,
equal-wf-T-base,
colength_wf_list,
less_than_transitivity1,
less_than_irreflexivity,
list-cases,
list_ind_nil_lemma,
length_of_nil_lemma,
product_subtype_list,
spread_cons_lemma,
intformeq_wf,
itermAdd_wf,
int_formula_prop_eq_lemma,
int_term_value_add_lemma,
decidable__le,
intformnot_wf,
int_formula_prop_not_lemma,
le_wf,
equal_wf,
subtract_wf,
itermSubtract_wf,
int_term_value_subtract_lemma,
subtype_base_sq,
set_subtype_base,
int_subtype_base,
decidable__equal_int,
list_ind_cons_lemma,
length_of_cons_lemma,
le_int_wf,
bool_wf,
assert_wf,
lt_int_wf,
bnot_wf,
eqtt_to_assert,
assert_of_le_int,
eqff_to_assert,
bool_cases_sqequal,
bool_subtype_base,
assert-bnot,
assert_of_lt_int,
uiff_transitivity,
assert_functionality_wrt_uiff,
bnot_of_le_int,
bnot_of_lt_int,
length_wf,
firstn_append,
decidable__lt,
add-is-int-iff,
false_wf,
lelt_wf,
non_neg_length
Rules used in proof :
sqequalSubstitution,
sqequalTransitivity,
computationStep,
sqequalReflexivity,
isect_memberFormation,
introduction,
cut,
thin,
lambdaFormation,
extract_by_obid,
sqequalHypSubstitution,
isectElimination,
hypothesisEquality,
hypothesis,
setElimination,
rename,
intWeakElimination,
natural_numberEquality,
independent_isectElimination,
dependent_pairFormation,
lambdaEquality,
int_eqEquality,
intEquality,
dependent_functionElimination,
isect_memberEquality,
voidElimination,
voidEquality,
sqequalRule,
independent_pairFormation,
computeAll,
independent_functionElimination,
sqequalAxiom,
applyEquality,
because_Cache,
unionElimination,
promote_hyp,
hypothesis_subsumption,
productElimination,
equalityTransitivity,
equalitySymmetry,
applyLambdaEquality,
dependent_set_memberEquality,
addEquality,
baseClosed,
instantiate,
cumulativity,
imageElimination,
equalityElimination,
pointwiseFunctionality,
baseApply,
closedConclusion
Latex:
\mforall{}[L1,L2:Top List]. \mforall{}[n:\mBbbN{}].
(firstn(n;L1 @ L2) \msim{} if n \mleq{}z ||L1|| then firstn(n;L1) else L1 @ firstn(n - ||L1||;L2) fi )
Date html generated:
2017_04_17-AM-08_00_17
Last ObjectModification:
2017_02_27-PM-04_31_09
Theory : list_1
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