Nuprl Lemma : select-front-as-reduce
∀[n:ℕ]. ∀[L:Top List].
  L[n] ~ hd(reduce(λu,x. if ||x|| <z n + 1 then x @ [u] else tl(x) @ [u] fi [];L)) supposing n < ||L||
Proof
Definitions occuring in Statement : 
select: L[n]
, 
hd: hd(l)
, 
length: ||as||
, 
append: as @ bs
, 
reduce: reduce(f;k;as)
, 
tl: tl(l)
, 
cons: [a / b]
, 
nil: []
, 
list: T List
, 
nat: ℕ
, 
ifthenelse: if b then t else f fi 
, 
lt_int: i <z j
, 
less_than: a < b
, 
uimplies: b supposing a
, 
uall: ∀[x:A]. B[x]
, 
top: Top
, 
lambda: λx.A[x]
, 
add: n + m
, 
natural_number: $n
, 
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)
, 
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)
, 
bfalse: ff
, 
bnot: ¬bb
, 
ifthenelse: if b then t else f fi 
, 
assert: ↑b
, 
le: A ≤ B
, 
int_seg: {i..j-}
, 
lelt: i ≤ j < k
, 
last: last(L)
, 
int_iseg: {i...j}
, 
cand: A c∧ B
, 
append: as @ bs
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, 
equal-wf-T-base, 
nat_wf, 
colength_wf_list, 
top_wf, 
less_than_transitivity1, 
less_than_irreflexivity, 
list-cases, 
reduce_nil_lemma, 
list_ind_nil_lemma, 
reverse_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, 
reduce_cons_lemma, 
list_wf, 
length_wf, 
le_int_wf, 
bool_wf, 
eqtt_to_assert, 
assert_of_le_int, 
length-reverse, 
eqff_to_assert, 
bool_cases_sqequal, 
bool_subtype_base, 
assert-bnot, 
lt_int_wf, 
firstn_wf, 
assert_wf, 
bnot_wf, 
uiff_transitivity, 
assert_of_lt_int, 
assert_functionality_wrt_uiff, 
bnot_of_lt_int, 
cons_wf, 
length_of_cons_lemma, 
non_neg_length, 
reverse-cons, 
list_ind_cons_lemma, 
append_firstn_lastn_sq, 
decidable__lt, 
lelt_wf, 
reverse-append, 
nth_tl_wf, 
nth_tl_decomp, 
length_nth_tl, 
length_of_nil_lemma, 
equal-wf-base, 
reduce_tl_cons_lemma, 
add-subtract-cancel, 
length_firstn, 
firstn_decomp, 
nil_wf, 
reduce_hd_cons_lemma, 
hd-reverse
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
isect_memberFormation, 
introduction, 
cut, 
lambdaFormation, 
thin, 
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, 
productEquality
Latex:
\mforall{}[n:\mBbbN{}].  \mforall{}[L:Top  List].
    L[n]  \msim{}  hd(reduce(\mlambda{}u,x.  if  ||x||  <z  n  +  1  then  x  @  [u]  else  tl(x)  @  [u]  fi  ;[];L))  supposing  n  <  ||\000CL||
Date html generated:
2018_05_21-PM-07_35_29
Last ObjectModification:
2017_07_26-PM-05_09_38
Theory : general
Home
Index