Nuprl Lemma : req-iff-rabs-rleq
∀x,y:ℝ.  (x = y ⇐⇒ ∀m:ℕ+. (|x - y| ≤ (r1/r(m))))
Proof
Definitions occuring in Statement : 
rdiv: (x/y), 
rleq: x ≤ y, 
rabs: |x|, 
rsub: x - y, 
req: x = y, 
int-to-real: r(n), 
real: ℝ, 
nat_plus: ℕ+, 
all: ∀x:A. B[x], 
iff: P ⇐⇒ Q, 
natural_number: $n
Definitions unfolded in proof : 
all: ∀x:A. B[x], 
iff: P ⇐⇒ Q, 
and: P ∧ Q, 
implies: P ⇒ Q, 
member: t ∈ T, 
prop: ℙ, 
uall: ∀[x:A]. B[x], 
rev_implies: P ⇐ Q, 
so_lambda: λ2x.t[x], 
nat_plus: ℕ+, 
uimplies: b supposing a, 
rneq: x ≠ y, 
guard: {T}, 
or: P ∨ Q, 
decidable: Dec(P), 
satisfiable_int_formula: satisfiable_int_formula(fmla), 
exists: ∃x:A. B[x], 
false: False, 
not: ¬A, 
top: Top, 
so_apply: x[s], 
subtype_rel: A ⊆r B, 
true: True, 
uiff: uiff(P;Q), 
rev_uimplies: rev_uimplies(P;Q), 
absval: |i|, 
itermConstant: "const", 
req_int_terms: t1 ≡ t2, 
rdiv: (x/y), 
squash: ↓T, 
sq_exists: ∃x:{A| B[x]}, 
rless: x < y
Lemmas referenced : 
nat_plus_wf, 
req_wf, 
all_wf, 
rleq_wf, 
rabs_wf, 
rsub_wf, 
rdiv_wf, 
int-to-real_wf, 
rless-int, 
nat_plus_properties, 
decidable__lt, 
satisfiable-full-omega-tt, 
intformand_wf, 
intformnot_wf, 
intformless_wf, 
itermConstant_wf, 
itermVar_wf, 
int_formula_prop_and_lemma, 
int_formula_prop_not_lemma, 
int_formula_prop_less_lemma, 
int_term_value_constant_lemma, 
int_term_value_var_lemma, 
int_formula_prop_wf, 
rless_wf, 
real_wf, 
absval_wf, 
rinv_wf2, 
rmul_wf, 
rleq-int-fractions2, 
decidable__le, 
intformle_wf, 
itermMultiply_wf, 
int_formula_prop_le_lemma, 
int_term_value_mul_lemma, 
rleq_functionality, 
rabs_functionality, 
rsub_functionality, 
req_weakening, 
uiff_transitivity2, 
real_term_polynomial, 
itermSubtract_wf, 
real_term_value_const_lemma, 
real_term_value_sub_lemma, 
real_term_value_var_lemma, 
req-iff-rsub-is-0, 
req_transitivity, 
real_term_value_mul_lemma, 
rinv-as-rdiv, 
squash_wf, 
true_wf, 
rabs-int, 
rless_transitivity1, 
rless_irreflexivity, 
small-reciprocal-real, 
req-iff-not-rneq, 
rneq-iff-rabs, 
rneq_wf, 
not_wf
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
lambdaFormation, 
independent_pairFormation, 
cut, 
introduction, 
extract_by_obid, 
hypothesis, 
sqequalHypSubstitution, 
isectElimination, 
thin, 
hypothesisEquality, 
sqequalRule, 
lambdaEquality, 
natural_numberEquality, 
setElimination, 
rename, 
because_Cache, 
independent_isectElimination, 
inrFormation, 
dependent_functionElimination, 
productElimination, 
independent_functionElimination, 
unionElimination, 
dependent_pairFormation, 
int_eqEquality, 
intEquality, 
isect_memberEquality, 
voidElimination, 
voidEquality, 
computeAll, 
applyEquality, 
minusEquality, 
multiplyEquality, 
imageElimination, 
equalityTransitivity, 
equalitySymmetry, 
imageMemberEquality, 
baseClosed, 
impliesFunctionality, 
addLevel, 
lemma_by_obid, 
dependent_set_memberEquality
Latex:
\mforall{}x,y:\mBbbR{}.    (x  =  y  \mLeftarrow{}{}\mRightarrow{}  \mforall{}m:\mBbbN{}\msupplus{}.  (|x  -  y|  \mleq{}  (r1/r(m))))
Date html generated:
2017_10_03-AM-09_06_12
Last ObjectModification:
2017_07_28-AM-07_41_59
Theory : reals
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