Nuprl Lemma : rmin-positive

x,y:ℝ.  ((rpositive(x) ∧ rpositive(y))  rpositive(rmin(x;y)))


Proof




Definitions occuring in Statement :  rpositive: rpositive(x) rmin: rmin(x;y) real: all: x:A. B[x] implies:  Q and: P ∧ Q
Definitions unfolded in proof :  all: x:A. B[x] rmin: rmin(x;y) implies:  Q and: P ∧ Q rpositive2: rpositive2(x) exists: x:A. B[x] member: t ∈ T uall: [x:A]. B[x] prop: nat_plus: + so_lambda: λ2x.t[x] real: so_apply: x[s] iff: ⇐⇒ Q rev_implies:  Q subtype_rel: A ⊆B uiff: uiff(P;Q) uimplies: supposing a guard: {T} squash: T true: True bool: 𝔹 unit: Unit it: btrue: tt ifthenelse: if then else fi  bfalse: ff or: P ∨ Q sq_type: SQType(T) bnot: ¬bb assert: b false: False not: ¬A le: A ≤ B decidable: Dec(P) subtract: m less_than': less_than'(a;b) satisfiable_int_formula: satisfiable_int_formula(fmla) top: Top nat: less_than: a < b
Lemmas referenced :  imax_nat_plus le_wf imax_wf nat_plus_wf all_wf imin_wf rpositive2_wf rpositive-iff rmin_wf rpositive_wf real_wf imax_lb squash_wf true_wf imax_unfold imin_unfold iff_weakening_equal le_int_wf bool_wf eqtt_to_assert assert_of_le_int eqff_to_assert equal_wf bool_cases_sqequal subtype_base_sq bool_subtype_base assert-bnot mul_preserves_le nat_plus_properties decidable__le decidable__lt false_wf not-lt-2 less-iff-le condition-implies-le minus-one-mul mul-commutes minus-one-mul-top add_functionality_wrt_le add-associates add-zero add-swap add-commutes zero-add le-add-cancel less_than_wf satisfiable-full-omega-tt intformand_wf intformnot_wf intformle_wf itermVar_wf itermMultiply_wf int_formula_prop_and_lemma int_formula_prop_not_lemma int_formula_prop_le_lemma int_term_value_var_lemma int_term_value_mul_lemma int_formula_prop_wf intformless_wf itermConstant_wf int_formula_prop_less_lemma int_term_value_constant_lemma mul_preserves_lt multiply-is-int-iff itermAdd_wf int_term_value_add_lemma minus-add minus-zero
Rules used in proof :  sqequalSubstitution sqequalTransitivity computationStep sqequalReflexivity lambdaFormation cut sqequalHypSubstitution productElimination thin dependent_pairFormation introduction extract_by_obid isectElimination because_Cache hypothesisEquality hypothesis sqequalRule setElimination rename lambdaEquality functionEquality multiplyEquality applyEquality productEquality addLevel impliesFunctionality independent_pairFormation independent_functionElimination andLevelFunctionality independent_isectElimination dependent_functionElimination imageElimination equalityTransitivity equalitySymmetry intEquality natural_numberEquality imageMemberEquality baseClosed universeEquality unionElimination equalityElimination promote_hyp instantiate cumulativity voidElimination dependent_set_memberEquality addEquality minusEquality int_eqEquality isect_memberEquality voidEquality computeAll pointwiseFunctionality baseApply closedConclusion

Latex:
\mforall{}x,y:\mBbbR{}.    ((rpositive(x)  \mwedge{}  rpositive(y))  {}\mRightarrow{}  rpositive(rmin(x;y)))



Date html generated: 2017_10_03-AM-08_24_33
Last ObjectModification: 2017_07_28-AM-07_23_23

Theory : reals


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