Nuprl Lemma : rational-lower-approx-property
∀x:ℝ. ∀n:ℕ+.  (((below x within 1/n) ≤ x) ∧ (x ≤ ((below x within 1/n) + (r1/r(n)))))
Proof
Definitions occuring in Statement : 
rational-lower-approx: (below x within 1/n)
, 
rdiv: (x/y)
, 
rleq: x ≤ y
, 
radd: a + b
, 
int-to-real: r(n)
, 
real: ℝ
, 
nat_plus: ℕ+
, 
all: ∀x:A. B[x]
, 
and: P ∧ Q
, 
natural_number: $n
Definitions unfolded in proof : 
all: ∀x:A. B[x]
, 
member: t ∈ T
, 
nat_plus: ℕ+
, 
uall: ∀[x:A]. B[x]
, 
decidable: Dec(P)
, 
or: P ∨ Q
, 
uimplies: b supposing a
, 
not: ¬A
, 
implies: P 
⇒ Q
, 
satisfiable_int_formula: satisfiable_int_formula(fmla)
, 
exists: ∃x:A. B[x]
, 
false: False
, 
top: Top
, 
and: P ∧ Q
, 
prop: ℙ
, 
rational-approx: (x within 1/n)
, 
rational-lower-approx: (below x within 1/n)
, 
real: ℝ
, 
has-value: (a)↓
, 
int_nzero: ℤ-o
, 
nequal: a ≠ b ∈ T 
, 
subtype_rel: A ⊆r B
, 
rneq: x ≠ y
, 
guard: {T}
, 
iff: P 
⇐⇒ Q
, 
rev_implies: P 
⇐ Q
, 
uiff: uiff(P;Q)
, 
rev_uimplies: rev_uimplies(P;Q)
, 
rat_term_to_real: rat_term_to_real(f;t)
, 
rtermSubtract: left "-" right
, 
rat_term_ind: rat_term_ind, 
rtermDivide: num "/" denom
, 
rtermConstant: "const"
, 
rtermVar: rtermVar(var)
, 
pi1: fst(t)
, 
true: True
, 
pi2: snd(t)
, 
cand: A c∧ B
, 
rge: x ≥ y
, 
req_int_terms: t1 ≡ t2
Lemmas referenced : 
rational-approx-property, 
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, 
istype-less_than, 
nat_plus_wf, 
real_wf, 
value-type-has-value, 
int-value-type, 
subtract_wf, 
int-rdiv_wf, 
intformeq_wf, 
int_formula_prop_eq_lemma, 
int_subtype_base, 
nequal_wf, 
int-to-real_wf, 
rsub_wf, 
rdiv_wf, 
rless-int, 
rless_wf, 
req_functionality, 
int-rdiv_functionality, 
req_inversion, 
rsub-int, 
req_weakening, 
int-rdiv-req, 
rsub_functionality, 
req-int-fractions, 
nat_plus_inc_int_nzero, 
decidable__equal_int, 
assert-rat-term-eq2, 
rtermDivide_wf, 
rtermSubtract_wf, 
rtermVar_wf, 
rtermConstant_wf, 
rleq_wf, 
radd_wf, 
rabs_wf, 
iff_weakening_uiff, 
rleq_functionality, 
radd_functionality, 
rabs-difference-bound-rleq, 
rleq_functionality_wrt_implies, 
rleq_weakening_equal, 
itermAdd_wf, 
int_term_value_add_lemma, 
req_transitivity, 
radd-rdiv, 
rdiv_functionality, 
radd-int, 
req_wf, 
rleq_weakening, 
itermSubtract_wf, 
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
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
lambdaFormation_alt, 
cut, 
introduction, 
extract_by_obid, 
sqequalHypSubstitution, 
dependent_functionElimination, 
thin, 
hypothesisEquality, 
dependent_set_memberEquality_alt, 
multiplyEquality, 
natural_numberEquality, 
setElimination, 
rename, 
hypothesis, 
isectElimination, 
unionElimination, 
independent_isectElimination, 
approximateComputation, 
independent_functionElimination, 
dependent_pairFormation_alt, 
lambdaEquality_alt, 
int_eqEquality, 
isect_memberEquality_alt, 
voidElimination, 
sqequalRule, 
independent_pairFormation, 
universeIsType, 
intEquality, 
applyEquality, 
because_Cache, 
inhabitedIsType, 
equalityIstype, 
equalityTransitivity, 
equalitySymmetry, 
callbyvalueReduce, 
baseApply, 
closedConclusion, 
baseClosed, 
sqequalBase, 
inrFormation_alt, 
productElimination, 
applyLambdaEquality, 
promote_hyp, 
addEquality
Latex:
\mforall{}x:\mBbbR{}.  \mforall{}n:\mBbbN{}\msupplus{}.    (((below  x  within  1/n)  \mleq{}  x)  \mwedge{}  (x  \mleq{}  ((below  x  within  1/n)  +  (r1/r(n)))))
Date html generated:
2019_10_29-AM-10_01_11
Last ObjectModification:
2019_04_02-AM-10_01_41
Theory : reals
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