Nuprl Lemma : rabs-difference-is-zero

∀x,y:ℝ.  (|x - y| = r0 ⇐⇒ x = y)


Proof




Definitions occuring in Statement :  rabs: |x|,  rsub: x - y,  req: x = y,  int-to-real: r(n),  real: ℝ,  all: ∀x:A. B[x],  iff: P ⇐⇒ Q,  natural_number: $n
Definitions unfolded in proof :  all: ∀x:A. B[x],  iff: P ⇐⇒ Q,  and: P ∧ Q,  implies: P ⇒ Q,  member: t ∈ T,  uall: ∀[x:A]. B[x],  prop: ℙ,  rev_implies: P ⇐ Q,  guard: {T},  uimplies: b 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


Home Index