Nuprl Lemma : approx-in-interval_wf
∀l:ℝ. ∀u:{u:ℝ| l ≤ u} . ∀x:{x:ℝ| x ∈ [l, u]} . ∀n:ℕ+.
  (approx-in-interval(l;u;x;n) ∈ {y:ℝ| (y ∈ [l, u]) ∧ (|x - y| ≤ (r(2)/r(n)))} )
Proof
Definitions occuring in Statement : 
approx-in-interval: approx-in-interval(l;u;x;n)
, 
rccint: [l, u]
, 
i-member: r ∈ I
, 
rdiv: (x/y)
, 
rleq: x ≤ y
, 
rabs: |x|
, 
rsub: x - y
, 
int-to-real: r(n)
, 
real: ℝ
, 
nat_plus: ℕ+
, 
all: ∀x:A. B[x]
, 
and: P ∧ Q
, 
member: t ∈ T
, 
set: {x:A| B[x]} 
, 
natural_number: $n
Definitions unfolded in proof : 
all: ∀x:A. B[x]
, 
member: t ∈ T
, 
top: Top
, 
approx-in-interval: approx-in-interval(l;u;x;n)
, 
has-value: (a)↓
, 
uall: ∀[x:A]. B[x]
, 
uimplies: b supposing a
, 
real: ℝ
, 
nat_plus: ℕ+
, 
decidable: Dec(P)
, 
or: P ∨ Q
, 
not: ¬A
, 
implies: P 
⇒ Q
, 
satisfiable_int_formula: satisfiable_int_formula(fmla)
, 
exists: ∃x:A. B[x]
, 
false: False
, 
and: P ∧ Q
, 
prop: ℙ
, 
bool: 𝔹
, 
unit: Unit
, 
it: ⋅
, 
btrue: tt
, 
uiff: uiff(P;Q)
, 
less_than: a < b
, 
less_than': less_than'(a;b)
, 
true: True
, 
squash: ↓T
, 
cand: A c∧ B
, 
sq_stable: SqStable(P)
, 
rneq: x ≠ y
, 
guard: {T}
, 
iff: P 
⇐⇒ Q
, 
rev_implies: P 
⇐ Q
, 
bfalse: ff
, 
sq_type: SQType(T)
, 
bnot: ¬bb
, 
ifthenelse: if b then t else f fi 
, 
assert: ↑b
, 
int_nzero: ℤ-o
, 
nequal: a ≠ b ∈ T 
, 
subtype_rel: A ⊆r B
, 
rev_uimplies: rev_uimplies(P;Q)
, 
req_int_terms: t1 ≡ t2
, 
rational-upper-approx: above x within 1/n
, 
rational-approx: (x within 1/n)
, 
so_lambda: λ2x.t[x]
, 
so_apply: x[s]
, 
rless: x < y
, 
sq_exists: ∃x:A [B[x]]
, 
rge: x ≥ y
, 
rational-lower-approx: (below x within 1/n)
, 
le: A ≤ B
Lemmas referenced : 
member_rccint_lemma, 
istype-void, 
value-type-has-value, 
int-value-type, 
lt_int_wf, 
nat_plus_properties, 
decidable__lt, 
full-omega-unsat, 
intformand_wf, 
intformnot_wf, 
intformless_wf, 
itermConstant_wf, 
itermMultiply_wf, 
itermVar_wf, 
istype-int, 
int_formula_prop_and_lemma, 
int_formula_prop_not_lemma, 
int_formula_prop_less_lemma, 
int_term_value_constant_lemma, 
int_term_value_mul_lemma, 
int_term_value_var_lemma, 
int_formula_prop_wf, 
istype-less_than, 
eqtt_to_assert, 
assert_of_lt_int, 
istype-top, 
rleq_weakening_equal, 
sq_stable__rleq, 
rleq_wf, 
rabs_wf, 
rsub_wf, 
rdiv_wf, 
int-to-real_wf, 
rless-int, 
rless_wf, 
eqff_to_assert, 
bool_cases_sqequal, 
subtype_base_sq, 
bool_wf, 
bool_subtype_base, 
assert-bnot, 
iff_weakening_uiff, 
assert_wf, 
less_than_wf, 
subtract_wf, 
int-rdiv_wf, 
intformeq_wf, 
int_formula_prop_eq_lemma, 
int_subtype_base, 
nequal_wf, 
nat_plus_wf, 
i-member_wf, 
rccint_wf, 
real_wf, 
radd-preserves-rleq, 
radd_wf, 
itermSubtract_wf, 
itermAdd_wf, 
rleq_functionality, 
rabs-of-nonneg, 
req_weakening, 
req-iff-rsub-is-0, 
real_polynomial_null, 
real_term_value_sub_lemma, 
real_term_value_add_lemma, 
real_term_value_var_lemma, 
real_term_value_const_lemma, 
set-value-type, 
mul_preserves_lt, 
set_subtype_base, 
rless_functionality, 
nat_plus_inc_int_nzero, 
int-rdiv-req, 
rless-int-fractions, 
add-is-int-iff, 
multiply-is-int-iff, 
int_term_value_add_lemma, 
false_wf, 
rational-approx-property, 
rational-upper-approx-property, 
rational-upper-approx_wf, 
rational-approx_wf, 
rabs-difference-bound-rleq, 
rleq_functionality_wrt_implies, 
rsub_functionality_wrt_rleq, 
req-int-fractions, 
decidable__equal_int, 
req_functionality, 
req_transitivity, 
radd-rdiv, 
rdiv_functionality, 
radd-int, 
rleq_weakening_rless, 
radd_functionality_wrt_rleq, 
rabs-difference-symmetry, 
subtract-is-int-iff, 
int_term_value_subtract_lemma, 
rational-lower-approx-property, 
rational-lower-approx_wf, 
rleq_transitivity, 
decidable__le, 
intformle_wf, 
int_formula_prop_le_lemma, 
mul_preserves_le, 
nat_plus_subtype_nat, 
rleq-int-fractions
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
lambdaFormation_alt, 
cut, 
sqequalRule, 
introduction, 
extract_by_obid, 
sqequalHypSubstitution, 
dependent_functionElimination, 
thin, 
isect_memberEquality_alt, 
voidElimination, 
hypothesis, 
callbyvalueReduce, 
isectElimination, 
intEquality, 
independent_isectElimination, 
applyEquality, 
setElimination, 
rename, 
hypothesisEquality, 
because_Cache, 
multiplyEquality, 
natural_numberEquality, 
addEquality, 
dependent_set_memberEquality_alt, 
unionElimination, 
approximateComputation, 
independent_functionElimination, 
dependent_pairFormation_alt, 
lambdaEquality_alt, 
int_eqEquality, 
independent_pairFormation, 
universeIsType, 
inhabitedIsType, 
equalityElimination, 
equalityTransitivity, 
equalitySymmetry, 
productElimination, 
lessCases, 
isect_memberFormation_alt, 
axiomSqEquality, 
isectIsTypeImplies, 
imageMemberEquality, 
baseClosed, 
imageElimination, 
productIsType, 
closedConclusion, 
inrFormation_alt, 
equalityIstype, 
promote_hyp, 
instantiate, 
cumulativity, 
baseApply, 
sqequalBase, 
setIsType, 
applyLambdaEquality, 
pointwiseFunctionality
Latex:
\mforall{}l:\mBbbR{}.  \mforall{}u:\{u:\mBbbR{}|  l  \mleq{}  u\}  .  \mforall{}x:\{x:\mBbbR{}|  x  \mmember{}  [l,  u]\}  .  \mforall{}n:\mBbbN{}\msupplus{}.
    (approx-in-interval(l;u;x;n)  \mmember{}  \{y:\mBbbR{}|  (y  \mmember{}  [l,  u])  \mwedge{}  (|x  -  y|  \mleq{}  (r(2)/r(n)))\}  )
Date html generated:
2019_10_30-AM-09_07_32
Last ObjectModification:
2019_10_10-PM-01_11_54
Theory : reals
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