Nuprl Lemma : rabs-difference-is-zero

x,y:ℝ.  (|x y| r0 ⇐⇒ y)


Proof




Definitions occuring in Statement :  rabs: |x| rsub: y req: y int-to-real: r(n) real: all: x:A. B[x] iff: ⇐⇒ Q natural_number: $n
Definitions unfolded in proof :  all: x:A. B[x] iff: ⇐⇒ Q and: P ∧ Q implies:  Q member: t ∈ T uall: [x:A]. B[x] prop: rev_implies:  Q guard: {T} uimplies: supposing a uiff: uiff(P;Q) req_int_terms: t1 ≡ t2 false: False not: ¬A top: Top decidable: Dec(P) or: P ∨ Q satisfiable_int_formula: satisfiable_int_formula(fmla) exists: x:A. B[x] rev_uimplies: rev_uimplies(P;Q) absval: |i|
Lemmas referenced :  req_wf rabs_wf rsub_wf int-to-real_wf real_wf rabs-difference-bound-rleq rleq_weakening rleq_antisymmetry rleq-implies-rleq radd_wf itermSubtract_wf itermAdd_wf itermVar_wf itermConstant_wf req-iff-rsub-is-0 real_polynomial_null istype-int real_term_value_sub_lemma istype-void real_term_value_add_lemma real_term_value_var_lemma real_term_value_const_lemma req-int decidable__equal_int full-omega-unsat intformnot_wf intformeq_wf int_formula_prop_not_lemma int_formula_prop_eq_lemma int_term_value_constant_lemma int_formula_prop_wf req_functionality rabs_functionality rsub_functionality req_weakening req_transitivity rabs-int
Rules used in proof :  sqequalSubstitution sqequalTransitivity computationStep sqequalReflexivity lambdaFormation_alt independent_pairFormation universeIsType cut introduction extract_by_obid sqequalHypSubstitution isectElimination thin hypothesisEquality hypothesis natural_numberEquality inhabitedIsType dependent_functionElimination productElimination independent_functionElimination independent_isectElimination because_Cache sqequalRule approximateComputation lambdaEquality_alt int_eqEquality isect_memberEquality_alt voidElimination minusEquality unionElimination dependent_pairFormation_alt

Latex:
\mforall{}x,y:\mBbbR{}.    (|x  -  y|  =  r0  \mLeftarrow{}{}\mRightarrow{}  x  =  y)



Date html generated: 2019_10_29-AM-10_00_19
Last ObjectModification: 2019_05_04-AM-11_14_07

Theory : reals


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