Nuprl Lemma : infinitesmal-difference
∀[x,y:ℝ].  uiff(x = y;∀[k:ℕ+]. (|x - y| ≤ (r1/r(k))))
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+
, 
uiff: uiff(P;Q)
, 
uall: ∀[x:A]. B[x]
, 
natural_number: $n
Definitions unfolded in proof : 
uiff: uiff(P;Q)
, 
and: P ∧ Q
, 
uimplies: b supposing a
, 
member: t ∈ T
, 
rev_implies: P 
⇐ Q
, 
uall: ∀[x:A]. B[x]
, 
so_lambda: λ2x.t[x]
, 
nat_plus: ℕ+
, 
rneq: x ≠ y
, 
guard: {T}
, 
or: P ∨ Q
, 
all: ∀x:A. B[x]
, 
iff: P 
⇐⇒ Q
, 
implies: P 
⇒ Q
, 
decidable: Dec(P)
, 
satisfiable_int_formula: satisfiable_int_formula(fmla)
, 
exists: ∃x:A. B[x]
, 
false: False
, 
not: ¬A
, 
top: Top
, 
prop: ℙ
, 
so_apply: x[s]
, 
rleq: x ≤ y
, 
rnonneg: rnonneg(x)
, 
le: A ≤ B
, 
subtype_rel: A ⊆r B
, 
itermConstant: "const"
, 
req_int_terms: t1 ≡ t2
Lemmas referenced : 
iff_weakening_uiff, 
uall_wf, 
nat_plus_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, 
req_wf, 
infinitesmal-zero, 
less_than'_wf, 
req_witness, 
uiff_wf, 
real_wf, 
req-implies-req, 
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
Rules used in proof : 
cut, 
addLevel, 
sqequalHypSubstitution, 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
productElimination, 
thin, 
independent_pairFormation, 
isect_memberFormation, 
introduction, 
independent_isectElimination, 
hypothesis, 
extract_by_obid, 
isectElimination, 
sqequalRule, 
lambdaEquality, 
hypothesisEquality, 
natural_numberEquality, 
setElimination, 
rename, 
because_Cache, 
inrFormation, 
dependent_functionElimination, 
independent_functionElimination, 
unionElimination, 
dependent_pairFormation, 
int_eqEquality, 
intEquality, 
isect_memberEquality, 
voidElimination, 
voidEquality, 
computeAll, 
independent_pairEquality, 
applyEquality, 
minusEquality, 
cumulativity, 
universeEquality, 
axiomEquality, 
equalityTransitivity, 
equalitySymmetry
Latex:
\mforall{}[x,y:\mBbbR{}].    uiff(x  =  y;\mforall{}[k:\mBbbN{}\msupplus{}].  (|x  -  y|  \mleq{}  (r1/r(k))))
Date html generated:
2017_10_03-AM-08_52_14
Last ObjectModification:
2017_07_28-AM-07_35_04
Theory : reals
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