Nuprl Lemma : real-vec-norm-diff-bound

∀[n:ℕ]. ∀[x,y:ℝ^n].  (|||x|| - ||y||| ≤ d(x;y))


Proof




Definitions occuring in Statement :  real-vec-dist: d(x;y),  real-vec-norm: ||x||,  real-vec: ℝ^n,  rleq: x ≤ y,  rabs: |x|,  rsub: x - y,  nat: ℕ,  uall: ∀[x:A]. B[x]
Definitions unfolded in proof :  uall: ∀[x:A]. B[x],  member: t ∈ T,  real-vec: ℝ^n,  int_seg: {i..j-},  lelt: i ≤ j < k,  and: P ∧ Q,  le: A ≤ B,  nat: ℕ,  rleq: x ≤ y,  rnonneg: rnonneg(x),  all: ∀x:A. B[x],  uimplies: b supposing a,  subtype_rel: A ⊆r B,  uiff: uiff(P;Q),  iff: P ⇐⇒ Q,  rev_implies: P ⇐ Q,  implies: P ⇒ Q,  cand: A c∧ B,  squash: ↓T,  prop: ℙ,  true: True,  guard: {T},  req_int_terms: t1 ≡ t2,  false: False,  not: ¬A,  top: Top
Lemmas referenced :  real-vec-triangle-inequality,  int-to-real_wf,  int_seg_wf,  le_witness_for_triv,  real-vec_wf,  istype-nat,  real-vec-dist_wf,  real-vec-norm_wf,  radd_wf,  rleq_functionality,  real-vec-dist-from-zero,  radd_functionality,  req_weakening,  rabs-difference-bound-rleq,  rleq-implies-rleq,  rsub_wf,  rleq_wf,  squash_wf,  true_wf,  real_wf,  radd_comm_eq,  subtype_rel_self,  iff_weakening_equal,  itermSubtract_wf,  itermAdd_wf,  itermVar_wf,  req-iff-rsub-is-0,  real-vec-dist-symmetry,  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
Rules used in proof :  sqequalSubstitution,  sqequalTransitivity,  computationStep,  sqequalReflexivity,  isect_memberFormation_alt,  introduction,  cut,  extract_by_obid,  sqequalHypSubstitution,  isectElimination,  thin,  hypothesisEquality,  sqequalRule,  lambdaEquality_alt,  setElimination,  rename,  productElimination,  hypothesis,  universeIsType,  natural_numberEquality,  dependent_functionElimination,  equalityTransitivity,  equalitySymmetry,  independent_isectElimination,  functionIsTypeImplies,  inhabitedIsType,  isect_memberEquality_alt,  isectIsTypeImplies,  because_Cache,  applyEquality,  independent_functionElimination,  independent_pairFormation,  imageElimination,  imageMemberEquality,  baseClosed,  instantiate,  universeEquality,  approximateComputation,  int_eqEquality,  voidElimination

Latex:
\mforall{}[n:\mBbbN{}].  \mforall{}[x,y:\mBbbR{}\^{}n].    (|||x||  -  ||y|||  \mleq{}  d(x;y))



Date html generated: 2019_10_30-AM-08_42_49
Last ObjectModification: 2019_07_08-AM-11_35_44

Theory : reals


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