Nuprl Lemma : qmin_lb

∀a,b,c:ℚ.  (qmin(b;c) ≤ a ⇐⇒ (b ≤ a) ∨ (c ≤ a))


Proof




Definitions occuring in Statement :  qmin: qmin(x;y),  qle: r ≤ s,  rationals: ℚ,  all: ∀x:A. B[x],  iff: P ⇐⇒ Q,  or: P ∨ Q
Definitions unfolded in proof :  all: ∀x:A. B[x],  qmin: qmin(x;y),  member: t ∈ T,  uall: ∀[x:A]. B[x],  iff: P ⇐⇒ Q,  and: P ∧ Q,  implies: P ⇒ Q,  or: P ∨ Q,  prop: ℙ,  rev_implies: P ⇐ Q,  guard: {T},  uimplies: b supposing a,  true: True,  uiff: uiff(P;Q),  bool: 𝔹,  unit: Unit,  it: ⋅,  btrue: tt,  ifthenelse: if b then t else f fi ,  bfalse: ff,  squash: ↓T
Lemmas referenced :  rationals_wf,  q_le_wf,  bool_wf,  equal-wf-T-base,  assert_wf,  qle_wf,  qle_transitivity_qorder,  or_wf,  bnot_wf,  not_wf,  qle_complement_qorder,  qless_transitivity_2_qorder,  qle_weakening_lt_qorder,  uiff_transitivity2,  eqtt_to_assert,  assert-q_le-eq,  uiff_transitivity,  eqff_to_assert,  assert_of_bnot,  squash_wf,  true_wf,  equal_wf
Rules used in proof :  sqequalSubstitution,  sqequalTransitivity,  computationStep,  sqequalReflexivity,  lambdaFormation,  cut,  introduction,  extract_by_obid,  hypothesis,  sqequalHypSubstitution,  isectElimination,  thin,  hypothesisEquality,  equalityTransitivity,  equalitySymmetry,  baseClosed,  because_Cache,  independent_pairFormation,  inlFormation,  unionElimination,  independent_isectElimination,  natural_numberEquality,  sqequalRule,  inrFormation,  productElimination,  equalityElimination,  independent_functionElimination,  applyEquality,  lambdaEquality,  imageElimination,  universeEquality,  imageMemberEquality,  dependent_functionElimination

Latex:
\mforall{}a,b,c:\mBbbQ{}.    (qmin(b;c)  \mleq{}  a  \mLeftarrow{}{}\mRightarrow{}  (b  \mleq{}  a)  \mvee{}  (c  \mleq{}  a))



Date html generated: 2018_05_21-PM-11_55_18
Last ObjectModification: 2017_07_26-PM-06_46_06

Theory : rationals


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