Nuprl Lemma : rexp-approx-for-small
∀N:ℕ+. ∀x:{x:ℝ| |x| ≤ (r1/r(4))} .  (∃z:ℤ [(|e^x - (r(z)/r(2 * N))| ≤ (r(2)/r(N)))])
Proof
Definitions occuring in Statement : 
rexp: e^x
, 
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]
, 
sq_exists: ∃x:A [B[x]]
, 
set: {x:A| B[x]} 
, 
multiply: n * m
, 
natural_number: $n
, 
int: ℤ
Definitions unfolded in proof : 
all: ∀x:A. B[x]
, 
member: t ∈ T
, 
sq_exists: ∃x:A [B[x]]
, 
uall: ∀[x:A]. B[x]
, 
uimplies: b supposing a
, 
rneq: x ≠ y
, 
guard: {T}
, 
or: P ∨ Q
, 
iff: P 
⇐⇒ Q
, 
and: P ∧ Q
, 
rev_implies: P 
⇐ Q
, 
implies: P 
⇒ Q
, 
nat: ℕ
, 
nat_plus: ℕ+
, 
ge: i ≥ j 
, 
decidable: Dec(P)
, 
not: ¬A
, 
satisfiable_int_formula: satisfiable_int_formula(fmla)
, 
exists: ∃x:A. B[x]
, 
false: False
, 
top: Top
, 
prop: ℙ
, 
less_than: a < b
, 
squash: ↓T
, 
less_than': less_than'(a;b)
, 
true: True
, 
subtype_rel: A ⊆r B
, 
le: A ≤ B
, 
uiff: uiff(P;Q)
, 
rev_uimplies: rev_uimplies(P;Q)
, 
rge: x ≥ y
, 
rdiv: (x/y)
, 
req_int_terms: t1 ≡ t2
Lemmas referenced : 
rexp-approx-lemma-ext, 
rexp-approx_wf, 
rleq_wf, 
rabs_wf, 
rsub_wf, 
rdiv_wf, 
int-to-real_wf, 
rless-int, 
nat_properties, 
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, 
istype-void, 
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, 
rless_wf, 
real_wf, 
nat_plus_wf, 
rexp_wf, 
radd_wf, 
exp_wf2, 
fact_wf, 
decidable__le, 
intformle_wf, 
int_formula_prop_le_lemma, 
istype-le, 
multiply-is-int-iff, 
false_wf, 
rleq-int-fractions, 
istype-less_than, 
rmul_preserves_rleq, 
rmul_wf, 
rinv_wf2, 
itermSubtract_wf, 
itermAdd_wf, 
rleq_weakening_equal, 
rleq_functionality_wrt_implies, 
rexp-poly-approx, 
radd_functionality_wrt_rleq, 
rleq_functionality, 
req_transitivity, 
rmul_functionality, 
req_weakening, 
rmul-rinv, 
rmul-int, 
req-iff-rsub-is-0, 
real_polynomial_null, 
real_term_value_sub_lemma, 
real_term_value_mul_lemma, 
real_term_value_add_lemma, 
real_term_value_const_lemma, 
real_term_value_var_lemma
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
lambdaFormation_alt, 
cut, 
introduction, 
extract_by_obid, 
sqequalHypSubstitution, 
dependent_functionElimination, 
thin, 
hypothesisEquality, 
setElimination, 
rename, 
dependent_set_memberFormation_alt, 
isectElimination, 
hypothesis, 
universeIsType, 
because_Cache, 
independent_isectElimination, 
sqequalRule, 
inrFormation_alt, 
productElimination, 
independent_functionElimination, 
unionElimination, 
natural_numberEquality, 
approximateComputation, 
dependent_pairFormation_alt, 
lambdaEquality_alt, 
int_eqEquality, 
isect_memberEquality_alt, 
voidElimination, 
independent_pairFormation, 
multiplyEquality, 
setIsType, 
closedConclusion, 
imageMemberEquality, 
baseClosed, 
applyEquality, 
dependent_set_memberEquality_alt, 
inhabitedIsType, 
equalityTransitivity, 
equalitySymmetry, 
pointwiseFunctionality, 
promote_hyp, 
baseApply
Latex:
\mforall{}N:\mBbbN{}\msupplus{}.  \mforall{}x:\{x:\mBbbR{}|  |x|  \mleq{}  (r1/r(4))\}  .    (\mexists{}z:\mBbbZ{}  [(|e\^{}x  -  (r(z)/r(2  *  N))|  \mleq{}  (r(2)/r(N)))])
Date html generated:
2019_10_30-AM-11_40_54
Last ObjectModification:
2019_02_04-AM-10_56_38
Theory : reals_2
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