Nuprl Lemma : qavg-between

∀[a,b:ℚ].  a < qavg(a;b) < b supposing a < b


Proof




Definitions occuring in Statement :  qavg: qavg(a;b),  q-between: a < b < c,  qless: r < s,  rationals: ℚ,  uimplies: b supposing a,  uall: ∀[x:A]. B[x]
Definitions unfolded in proof :  uall: ∀[x:A]. B[x],  member: t ∈ T,  uimplies: b supposing a,  qavg: qavg(a;b),  q-between: a < b < c,  and: P ∧ Q,  implies: P ⇒ Q,  prop: ℙ,  subtype_rel: A ⊆r B,  qless: r < s,  grp_lt: a < b,  set_lt: a <p b,  assert: ↑b,  ifthenelse: if b then t else f fi ,  set_blt: a <b b,  band: p ∧b q,  infix_ap: x f y,  set_le: ≤b,  pi2: snd(t),  oset_of_ocmon: g↓oset,  dset_of_mon: g↓set,  grp_le: ≤b,  pi1: fst(t),  qadd_grp: <ℚ+>,  q_le: q_le(r;s),  callbyvalueall: callbyvalueall,  evalall: evalall(t),  bor: p ∨bq,  qpositive: qpositive(r),  qsub: r - s,  qadd: r + s,  qmul: r * s,  btrue: tt,  lt_int: i <z j,  bnot: ¬bb,  bfalse: ff,  qeq: qeq(r;s),  eq_int: (i =z j),  true: True,  uiff: uiff(P;Q),  cand: A c∧ B,  rev_uimplies: rev_uimplies(P;Q),  squash: ↓T,  not: ¬A,  false: False,  guard: {T},  iff: P ⇐⇒ Q,  rev_implies: P ⇐ Q
Lemmas referenced :  qadd_comm_q,  q_distrib,  qmul_ident,  qadd_preserves_qless,  iff_weakening_equal,  equal_wf,  assert-qeq,  qmul-qdiv-cancel,  true_wf,  squash_wf,  qadd_wf,  qdiv_wf,  qmul_wf,  int-subtype-rationals,  qmul_preserves_qless,  rationals_wf,  qless_wf,  qavg_wf,  qless_witness
Rules used in proof :  sqequalSubstitution,  sqequalTransitivity,  computationStep,  sqequalReflexivity,  isect_memberFormation,  introduction,  cut,  sqequalRule,  sqequalHypSubstitution,  productElimination,  thin,  independent_pairEquality,  lemma_by_obid,  isectElimination,  hypothesisEquality,  hypothesis,  independent_functionElimination,  because_Cache,  isect_memberEquality,  equalityTransitivity,  equalitySymmetry,  natural_numberEquality,  applyEquality,  independent_isectElimination,  independent_pairFormation,  lambdaEquality,  imageElimination,  lambdaFormation,  voidElimination,  imageMemberEquality,  baseClosed,  universeEquality

Latex:
\mforall{}[a,b:\mBbbQ{}].    a  <  qavg(a;b)  <  b  supposing  a  <  b



Date html generated: 2016_05_15-PM-11_06_06
Last ObjectModification: 2016_01_16-PM-09_28_21

Theory : rationals


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