Nuprl Lemma : square-between

a:{a:ℚ0 ≤ a} . ∀b:{b:ℚa < b} .  (∃r:ℚ [(a < r < b ∧ 0 < r)])


Proof




Definitions occuring in Statement :  q-between: a < b < c qle: r ≤ s qless: r < s qmul: s rationals: 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:  Q prop: so_lambda: λ2x.t[x] and: P ∧ Q subtype_rel: A ⊆B so_apply: x[s] uimplies: supposing a nat_plus: + 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: 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: s qpositive: qpositive(r) qmul: s ifthenelse: if then else fi  btrue: tt qadd: 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: ⇐⇒ Q rev_implies:  Q mk-rational: mk-rational(a;b) q_less: q_less(r;s) cand: c∧ B nat: sq_exists: x:A [B[x]] let: let ge: i ≥  int_nzero: -o nequal: a ≠ b ∈  true: True less_than: a < b le: A ≤ B subtract: 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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