Nuprl Lemma : rat-zero-cases
∀x:ℤ × ℕ+. ((↓r0 ≤ ratreal(x)) ∨ (↓ratreal(x) ≤ r0))
Proof
Definitions occuring in Statement : 
ratreal: ratreal(r), 
rleq: x ≤ y, 
int-to-real: r(n), 
nat_plus: ℕ+, 
all: ∀x:A. B[x], 
squash: ↓T, 
or: P ∨ Q, 
product: x:A × B[x], 
natural_number: $n, 
int: ℤ
Definitions unfolded in proof : 
all: ∀x:A. B[x], 
member: t ∈ T, 
subtype_rel: A ⊆r B, 
uall: ∀[x:A]. B[x], 
or: P ∨ Q, 
prop: ℙ, 
nat_plus: ℕ+, 
decidable: Dec(P), 
uimplies: b supposing a, 
not: ¬A, 
implies: P ⇒ Q, 
satisfiable_int_formula: satisfiable_int_formula(fmla), 
exists: ∃x:A. B[x], 
top: Top, 
false: False, 
rat-rleq-cases-ext, 
exposed-it: exposed-it, 
bool: 𝔹, 
unit: Unit, 
it: ⋅, 
btrue: tt, 
uiff: uiff(P;Q), 
and: P ∧ Q, 
less_than: a < b, 
less_than': less_than'(a;b), 
true: True, 
squash: ↓T, 
bfalse: ff, 
sq_type: SQType(T), 
guard: {T}, 
bnot: ¬bb, 
ifthenelse: if b then t else f fi , 
assert: ↑b, 
rev_implies: P ⇐ Q, 
iff: P ⇐⇒ Q, 
rneq: x ≠ y, 
le: A ≤ B
Lemmas referenced : 
istype-int, 
nat_plus_wf, 
rat-rleq-cases-ext, 
subtype_rel_self, 
squash_wf, 
rleq_wf, 
ratreal_wf, 
decidable__lt, 
full-omega-unsat, 
intformnot_wf, 
intformless_wf, 
itermConstant_wf, 
int_formula_prop_not_lemma, 
istype-void, 
int_formula_prop_less_lemma, 
int_term_value_constant_lemma, 
int_formula_prop_wf, 
istype-less_than, 
lt_int_wf, 
eqtt_to_assert, 
assert_of_lt_int, 
istype-top, 
eqff_to_assert, 
bool_cases_sqequal, 
subtype_base_sq, 
bool_wf, 
bool_subtype_base, 
assert-bnot, 
iff_weakening_uiff, 
assert_wf, 
less_than_wf, 
nat_plus_properties, 
intformand_wf, 
itermMultiply_wf, 
itermVar_wf, 
int_formula_prop_and_lemma, 
int_term_value_mul_lemma, 
int_term_value_var_lemma, 
int-to-real_wf, 
rdiv_wf, 
rless-int, 
rless_wf, 
rleq-int-fractions2, 
istype-false, 
rleq_transitivity, 
rleq-int-fractions3, 
rleq_functionality, 
ratreal-req, 
req_weakening
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
lambdaFormation_alt, 
productIsType, 
cut, 
introduction, 
extract_by_obid, 
hypothesis, 
universeIsType, 
applyEquality, 
thin, 
instantiate, 
sqequalRule, 
sqequalHypSubstitution, 
isectElimination, 
functionEquality, 
productEquality, 
intEquality, 
unionEquality, 
hypothesisEquality, 
independent_pairEquality, 
natural_numberEquality, 
dependent_set_memberEquality_alt, 
dependent_functionElimination, 
unionElimination, 
independent_isectElimination, 
approximateComputation, 
independent_functionElimination, 
dependent_pairFormation_alt, 
lambdaEquality_alt, 
isect_memberEquality_alt, 
voidElimination, 
productElimination, 
multiplyEquality, 
setElimination, 
rename, 
inhabitedIsType, 
equalityElimination, 
because_Cache, 
lessCases, 
isect_memberFormation_alt, 
axiomSqEquality, 
isectIsTypeImplies, 
independent_pairFormation, 
imageMemberEquality, 
baseClosed, 
imageElimination, 
equalityTransitivity, 
equalitySymmetry, 
equalityIstype, 
promote_hyp, 
cumulativity, 
int_eqEquality, 
inlFormation_alt, 
inrFormation_alt, 
closedConclusion
Latex:
\mforall{}x:\mBbbZ{}  \mtimes{}  \mBbbN{}\msupplus{}.  ((\mdownarrow{}r0  \mleq{}  ratreal(x))  \mvee{}  (\mdownarrow{}ratreal(x)  \mleq{}  r0))
Date html generated:
2019_10_30-AM-09_29_04
Last ObjectModification:
2019_01_11-AM-11_56_49
Theory : reals
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