Nuprl Lemma : int-rdiv-is-positive
∀x:ℝ. ∀k:ℤ-o.  (r0 < (x)/k 
⇐⇒ ((r0 < x) ∧ 0 < k) ∨ ((x < r0) ∧ k < 0))
Proof
Definitions occuring in Statement : 
rless: x < y
, 
int-rdiv: (a)/k1
, 
int-to-real: r(n)
, 
real: ℝ
, 
int_nzero: ℤ-o
, 
less_than: a < b
, 
all: ∀x:A. B[x]
, 
iff: P 
⇐⇒ Q
, 
or: P ∨ Q
, 
and: 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
, 
uall: ∀[x:A]. B[x]
, 
prop: ℙ
, 
rev_implies: P 
⇐ Q
, 
or: P ∨ Q
, 
int_nzero: ℤ-o
, 
uimplies: b supposing a
, 
not: ¬A
, 
rless: x < y
, 
sq_exists: ∃x:A [B[x]]
, 
false: False
, 
nat_plus: ℕ+
, 
nequal: a ≠ b ∈ T 
, 
satisfiable_int_formula: satisfiable_int_formula(fmla)
, 
exists: ∃x:A. B[x]
, 
top: Top
, 
subtype_rel: A ⊆r B
, 
so_lambda: λ2x.t[x]
, 
so_apply: x[s]
Lemmas referenced : 
rless_wf, 
int-to-real_wf, 
int-rdiv_wf, 
istype-less_than, 
int_nzero_wf, 
real_wf, 
rdiv_wf, 
rneq-int, 
nat_plus_properties, 
int_nzero_properties, 
full-omega-unsat, 
intformand_wf, 
intformeq_wf, 
itermVar_wf, 
itermConstant_wf, 
intformnot_wf, 
istype-int, 
int_formula_prop_and_lemma, 
istype-void, 
int_formula_prop_eq_lemma, 
int_term_value_var_lemma, 
int_term_value_constant_lemma, 
int_formula_prop_not_lemma, 
int_formula_prop_wf, 
set_subtype_base, 
nequal_wf, 
int_subtype_base, 
rless_functionality, 
req_weakening, 
int-rdiv-req, 
rdiv-is-positive, 
rless-int
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
lambdaFormation_alt, 
independent_pairFormation, 
universeIsType, 
cut, 
introduction, 
extract_by_obid, 
sqequalHypSubstitution, 
isectElimination, 
thin, 
natural_numberEquality, 
hypothesis, 
hypothesisEquality, 
sqequalRule, 
unionIsType, 
productIsType, 
setElimination, 
rename, 
because_Cache, 
independent_isectElimination, 
dependent_functionElimination, 
productElimination, 
independent_functionElimination, 
approximateComputation, 
dependent_pairFormation_alt, 
lambdaEquality_alt, 
int_eqEquality, 
isect_memberEquality_alt, 
voidElimination, 
equalityIstype, 
applyEquality, 
intEquality, 
baseClosed, 
sqequalBase, 
equalitySymmetry, 
unionElimination, 
inlFormation_alt, 
promote_hyp, 
inrFormation_alt
Latex:
\mforall{}x:\mBbbR{}.  \mforall{}k:\mBbbZ{}\msupminus{}\msupzero{}.    (r0  <  (x)/k  \mLeftarrow{}{}\mRightarrow{}  ((r0  <  x)  \mwedge{}  0  <  k)  \mvee{}  ((x  <  r0)  \mwedge{}  k  <  0))
Date html generated:
2019_10_29-AM-10_05_55
Last ObjectModification:
2019_04_01-PM-11_11_32
Theory : reals
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