Nuprl Lemma : square-between

∀a:{a:ℚ| 0 ≤ a} . ∀b:{b:ℚ| a < b} .  (∃r:ℚ [(a < r * r < b ∧ 0 < r)])


Proof




Definitions occuring in Statement :  q-between: a < b < c,  qle: r ≤ s,  qless: r < s,  qmul: r * s,  rationals: ℚ,  all: ∀x:A. B[x],  sq_exists: ∃x:A [B[x]],  and: P ∧ Q,  set: {x:A| B[x]} ,  natural_number: $n
Definitions unfolded in proof :  all: ∀x:A. B[x],  uall: ∀[x:A]. B[x],  member: t ∈ T,  implies: P ⇒ Q,  prop: ℙ,  so_lambda: λ2x.t[x],  and: P ∧ Q,  subtype_rel: A ⊆r B,  so_apply: x[s],  uimplies: b supposing a,  nat_plus: ℕ+,  sq_type: SQType(T),  guard: {T},  sq_stable: SqStable(P),  squash: ↓T,  qle: r ≤ s,  grp_leq: a ≤ b,  qadd_grp: <ℚ+>,  grp_le: ≤b,  pi2: snd(t),  pi1: fst(t),  infix_ap: x f y,  q_le: q_le(r;s),  callbyvalueall: callbyvalueall,  evalall: evalall(t),  has-value: (a)↓,  has-valueall: has-valueall(a),  qeq: qeq(r;s),  qsub: r - s,  qpositive: qpositive(r),  qmul: r * s,  ifthenelse: if b then t else f fi ,  btrue: tt,  qadd: r + s,  bfalse: ff,  or: P ∨ Q,  uiff: uiff(P;Q),  band: p ∧b q,  decidable: Dec(P),  not: ¬A,  satisfiable_int_formula: satisfiable_int_formula(fmla),  exists: ∃x:A. B[x],  false: False,  top: Top,  iff: P ⇐⇒ Q,  rev_implies: P ⇐ Q,  mk-rational: mk-rational(a;b),  q_less: q_less(r;s),  cand: A c∧ B,  nat: ℕ,  sq_exists: ∃x:A [B[x]],  let: let,  ge: i ≥ j ,  int_nzero: ℤ-o,  nequal: a ≠ b ∈ T ,  true: True,  less_than: a < b,  le: A ≤ B,  subtract: n - m,  q-between: a < b < c,  rev_uimplies: rev_uimplies(P;Q)
Lemmas referenced :  equals-qrep,  qrep-denom,  sq_exists_wf,  rationals_wf,  q-between_wf,  qrep_wf,  qmul_wf,  qless_wf,  qle_wf,  int-subtype-rationals,  subtype_base_sq,  nat_plus_wf,  product_subtype_base,  int_subtype_base,  set_subtype_base,  less_than_wf,  sq_stable_from_decidable,  decidable__qle,  valueall-type-has-valueall,  product-valueall-type,  int-valueall-type,  set-valueall-type,  evalall-reduce,  assert_wf,  bor_wf,  lt_int_wf,  bool_cases,  bool_wf,  bool_subtype_base,  eqtt_to_assert,  band_wf,  btrue_wf,  assert_of_lt_int,  bfalse_wf,  eq_int_wf,  equal-wf-base,  istype-assert,  istype-less_than,  nat_plus_properties,  decidable__le,  full-omega-unsat,  intformand_wf,  intformnot_wf,  intformle_wf,  itermConstant_wf,  itermVar_wf,  intformor_wf,  intformless_wf,  itermAdd_wf,  itermMultiply_wf,  istype-int,  int_formula_prop_and_lemma,  istype-void,  int_formula_prop_not_lemma,  int_formula_prop_le_lemma,  int_term_value_constant_lemma,  int_term_value_var_lemma,  int_formula_prop_or_lemma,  int_formula_prop_less_lemma,  int_term_value_add_lemma,  int_term_value_mul_lemma,  int_formula_prop_wf,  intformeq_wf,  int_formula_prop_eq_lemma,  iff_transitivity,  iff_weakening_uiff,  assert_of_bor,  assert_of_band,  assert_of_eq_int,  decidable__qless,  assert-q_less-eq,  mk-rational_wf,  nat_plus_inc_int_nzero,  iff_weakening_equal,  mul_bounds_1b,  decidable__lt,  bnot_wf,  not_wf,  eqff_to_assert,  assert_of_bnot,  mul_bounds_1a,  istype-le,  nat_plus_subtype_nat,  isqrt_wf,  nat_properties,  add_nat_plus,  add-is-int-iff,  false_wf,  qdiv_wf,  multiply_nat_wf,  int_nzero-rational,  int_entire_a,  nequal_wf,  mul_nat_plus,  isqrt-property,  equal_wf,  squash_wf,  true_wf,  istype-universe,  subtype_rel_self,  add_functionality_wrt_eq,  istype-nat,  itermMinus_wf,  int_term_value_minus_lemma,  mul_preserves_lt,  nat_wf,  le_wf,  decidable__equal_int,  mul-distributes,  mul-distributes-right,  add-associates,  mul-swap,  mul-commutes,  mul-associates,  one-mul,  two-mul,  add-commutes,  add-swap,  subtract_wf,  itermSubtract_wf,  int_term_value_subtract_lemma,  mul_preserves_le,  mk-rational-qdiv,  qmul_preserves_qless,  qless-int,  subtype_rel_set,  qmul-mul,  qmul_assoc_qrng,  qmul_comm_qrng,  qmul_ac_1_qrng,  qmul-qdiv-cancel3,  qless_transitivity_2_qorder,  qle_weakening_eq_qorder,  qless_irreflexivity,  qmul_zero_qrng,  qmul-qdiv-cancel
Rules used in proof :  sqequalSubstitution,  sqequalTransitivity,  computationStep,  sqequalReflexivity,  lambdaFormation_alt,  cut,  introduction,  extract_by_obid,  sqequalHypSubstitution,  isectElimination,  thin,  setElimination,  rename,  hypothesisEquality,  hypothesis,  equalitySymmetry,  because_Cache,  equalityTransitivity,  inhabitedIsType,  productElimination,  equalityIstype,  dependent_functionElimination,  independent_functionElimination,  hyp_replacement,  applyLambdaEquality,  sqequalRule,  lambdaEquality_alt,  productEquality,  natural_numberEquality,  applyEquality,  setIsType,  universeIsType,  instantiate,  cumulativity,  intEquality,  independent_isectElimination,  imageMemberEquality,  baseClosed,  imageElimination,  callbyvalueReduce,  sqleReflexivity,  isintReduceTrue,  independent_pairEquality,  addEquality,  multiplyEquality,  unionElimination,  unionEquality,  baseApply,  closedConclusion,  isect_memberEquality_alt,  productIsType,  unionIsType,  sqequalBase,  approximateComputation,  dependent_pairFormation_alt,  int_eqEquality,  voidElimination,  independent_pairFormation,  inlFormation_alt,  promote_hyp,  inrFormation_alt,  functionIsType,  dependent_set_memberEquality_alt,  dependent_set_memberFormation_alt,  pointwiseFunctionality,  universeEquality,  minusEquality

Latex:
\mforall{}a:\{a:\mBbbQ{}|  0  \mleq{}  a\}  .  \mforall{}b:\{b:\mBbbQ{}|  a  <  b\}  .    (\mexists{}r:\mBbbQ{}  [(a  <  r  *  r  <  b  \mwedge{}  0  <  r)])



Date html generated: 2019_10_16-PM-00_38_33
Last ObjectModification: 2019_06_26-PM-04_14_56

Theory : rationals


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