Nuprl Lemma : rpositive-rmul

x,y:ℝ.  (rpositive(x)  rpositive(y)  rpositive(x y))


Proof




Definitions occuring in Statement :  rpositive: rpositive(x) rmul: b real: all: x:A. B[x] implies:  Q
Definitions unfolded in proof :  all: x:A. B[x] implies:  Q rmul: b has-value: (a)↓ uall: [x:A]. B[x] member: t ∈ T nat_plus: + subtype_rel: A ⊆B int_upper: {i...} so_lambda: λ2x.t[x] real: so_apply: x[s] prop: iff: ⇐⇒ Q and: P ∧ Q rev_implies:  Q rpositive2: rpositive2(x) exists: x:A. B[x] nat: true: True bool: 𝔹 unit: Unit it: btrue: tt uiff: uiff(P;Q) uimplies: supposing a ifthenelse: if then else fi  le: A ≤ B less_than': less_than'(a;b) false: False not: ¬A less_than: a < b squash: T guard: {T} decidable: Dec(P) or: P ∨ Q satisfiable_int_formula: satisfiable_int_formula(fmla) top: Top bfalse: ff sq_type: SQType(T) bnot: ¬bb assert: b cand: c∧ B reg-seq-mul: reg-seq-mul(x;y) nequal: a ≠ b ∈  int_nzero: -o sq_stable: SqStable(P) rev_uimplies: rev_uimplies(P;Q) ge: i ≥  gt: i > j
Lemmas referenced :  real-has-value rpositive2_functionality accelerate_wf imax_wf canonical-bound_wf int_upper_wf all_wf nat_plus_wf le_wf absval_wf less_than_wf reg-seq-mul_wf2 reg-seq-mul_wf accelerate-bdd-diff rpositive2_wf rpositive-iff rmul_wf rpositive_wf real_wf nat_wf ifthenelse_wf le_int_wf bool_wf eqtt_to_assert assert_of_le_int add_nat_plus multiply_nat_wf subtype_rel_set int_upper_subtype_nat false_wf nat_plus_properties decidable__lt satisfiable-full-omega-tt intformand_wf intformnot_wf intformless_wf itermConstant_wf itermVar_wf itermAdd_wf itermMultiply_wf intformeq_wf int_formula_prop_and_lemma int_formula_prop_not_lemma int_formula_prop_less_lemma int_term_value_constant_lemma int_term_value_var_lemma int_term_value_add_lemma int_term_value_mul_lemma int_formula_prop_eq_lemma int_formula_prop_wf equal_wf eqff_to_assert bool_cases_sqequal subtype_base_sq bool_subtype_base assert-bnot add-is-int-iff multiply-is-int-iff squash_wf true_wf add_functionality_wrt_eq imax_unfold iff_weakening_equal imax_nat_plus multiply_nat_plus imax_ub decidable__le intformle_wf int_formula_prop_le_lemma mul_nat_plus mul_preserves_le nat_plus_subtype_nat mul_preserves_lt mul_cancel_in_le equal-wf-base mul-swap div_rem_sum2 nequal_wf left_mul_subtract_distrib rem_bounds_absval set_wf int_subtype_base decidable__equal_int sq_stable__less_than le_functionality le_weakening multiply_functionality_wrt_le sq_stable__le absval_pos neg_mul_arg_bounds gt_wf mul_bounds_1a subtract_wf itermSubtract_wf int_term_value_subtract_lemma
Rules used in proof :  sqequalSubstitution sqequalTransitivity computationStep sqequalReflexivity lambdaFormation cut sqequalRule callbyvalueReduce introduction extract_by_obid sqequalHypSubstitution isectElimination thin hypothesisEquality hypothesis dependent_functionElimination dependent_set_memberEquality addEquality multiplyEquality natural_numberEquality applyEquality lambdaEquality setElimination rename setEquality because_Cache independent_functionElimination productElimination addLevel impliesFunctionality functionEquality intEquality unionElimination equalityElimination equalityTransitivity equalitySymmetry independent_isectElimination independent_pairFormation imageMemberEquality baseClosed applyLambdaEquality dependent_pairFormation int_eqEquality isect_memberEquality voidElimination voidEquality computeAll promote_hyp instantiate cumulativity pointwiseFunctionality baseApply closedConclusion imageElimination universeEquality inlFormation inrFormation productEquality divideEquality remainderEquality

Latex:
\mforall{}x,y:\mBbbR{}.    (rpositive(x)  {}\mRightarrow{}  rpositive(y)  {}\mRightarrow{}  rpositive(x  *  y))



Date html generated: 2017_10_03-AM-08_23_29
Last ObjectModification: 2017_07_28-AM-07_22_53

Theory : reals


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