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: + all: x:A. B[x] squash: T or: P ∨ Q product: x:A × B[x] natural_number: $n int:
Definitions unfolded in proof :  all: x:A. B[x] member: t ∈ T subtype_rel: A ⊆B uall: [x:A]. B[x] or: P ∨ Q prop: nat_plus: + decidable: Dec(P) uimplies: supposing a not: ¬A implies:  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 then else fi  assert: b rev_implies:  Q iff: ⇐⇒ 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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