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: int_nzero: -o less_than: a < b all: x:A. B[x] iff: ⇐⇒ Q or: P ∨ Q and: P ∧ Q natural_number: $n
Definitions unfolded in proof :  all: x:A. B[x] iff: ⇐⇒ Q and: P ∧ Q implies:  Q member: t ∈ T uall: [x:A]. B[x] prop: rev_implies:  Q or: P ∨ Q int_nzero: -o uimplies: supposing a not: ¬A rless: x < y sq_exists: x:A [B[x]] false: False nat_plus: + nequal: a ≠ b ∈  satisfiable_int_formula: satisfiable_int_formula(fmla) exists: x:A. B[x] top: Top subtype_rel: A ⊆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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