Nuprl Lemma : rv-pos-angle-lemma

∀n:ℕ. ∀x,y:ℝ^n.  ((||x|| = ||y||) ⇒ (r0 < d(x;y)) ⇒ (r0 < d(r(-1)*x;y)) ⇒ (|x⋅y| < (||x|| * ||y||)))


Proof




Definitions occuring in Statement :  real-vec-dist: d(x;y),  real-vec-norm: ||x||,  dot-product: x⋅y,  real-vec-mul: a*X,  real-vec: ℝ^n,  rless: x < y,  rabs: |x|,  req: x = y,  rmul: a * b,  int-to-real: r(n),  nat: ℕ,  all: ∀x:A. B[x],  implies: P ⇒ Q,  minus: -n,  natural_number: $n
Definitions unfolded in proof :  all: ∀x:A. B[x],  implies: P ⇒ Q,  member: t ∈ T,  uall: ∀[x:A]. B[x],  uimplies: b supposing a,  and: P ∧ Q,  prop: ℙ,  subtype_rel: A ⊆r B,  nat: ℕ,  le: A ≤ B,  less_than': less_than'(a;b),  false: False,  not: ¬A,  iff: P ⇐⇒ Q,  rev_implies: P ⇐ Q,  real-vec-dist: d(x;y),  uiff: uiff(P;Q),  rev_uimplies: rev_uimplies(P;Q),  less_than: a < b,  squash: ↓T,  or: P ∨ Q,  rsub: x - y,  cand: A c∧ B,  nat_plus: ℕ+,  true: True
Lemmas referenced :  square-rless-implies,  rabs_wf,  dot-product_wf,  rmul_wf,  real-vec-norm_wf,  rmul-nonneg-case1,  real-vec-norm-nonneg,  rless_wf,  int-to-real_wf,  real-vec-dist_wf,  real-vec-mul_wf,  real_wf,  rleq_wf,  req_wf,  real-vec_wf,  nat_wf,  rnexp_wf,  false_wf,  le_wf,  rnexp2-nonneg,  rless_functionality,  req_inversion,  rabs-rnexp,  rnexp-rmul,  rabs-of-nonneg,  rmul_functionality,  real-vec-norm-squared,  rnexp2,  req_weakening,  rnexp-positive,  real-vec-sub_wf,  radd_wf,  real-vec-norm-diff-squared,  radd_functionality,  dot-product-linearity2,  req_transitivity,  rmul-assoc,  rmul-int,  rmul-one-both,  radd-assoc,  radd_comm,  req_functionality,  rnexp_functionality,  radd-preserves-req,  rsub_wf,  rminus_wf,  rmul-is-positive,  rless-int,  less_than_wf,  or_wf,  uiff_transitivity,  rmul-identity1,  rmul-distrib2,  radd-int,  rmul-distrib,  rmul_over_rminus,  radd-ac,  radd-rminus-both,  radd-zero-both,  rmul-zero-both,  radd-preserves-rless,  rabs-rless-iff,  rminus-as-rmul,  rnexp-rless,  zero-rleq-rabs
Rules used in proof :  sqequalSubstitution,  sqequalTransitivity,  computationStep,  sqequalReflexivity,  lambdaFormation,  cut,  introduction,  extract_by_obid,  sqequalHypSubstitution,  dependent_functionElimination,  thin,  isectElimination,  hypothesisEquality,  hypothesis,  independent_functionElimination,  independent_isectElimination,  independent_pairFormation,  because_Cache,  natural_numberEquality,  minusEquality,  applyEquality,  lambdaEquality,  setElimination,  rename,  setEquality,  sqequalRule,  dependent_set_memberEquality,  productElimination,  multiplyEquality,  promote_hyp,  addEquality,  addLevel,  orFunctionality,  andLevelFunctionality,  imageElimination,  voidElimination,  productEquality,  unionElimination,  imageMemberEquality,  baseClosed

Latex:
\mforall{}n:\mBbbN{}.  \mforall{}x,y:\mBbbR{}\^{}n.
    ((||x||  =  ||y||)  {}\mRightarrow{}  (r0  <  d(x;y))  {}\mRightarrow{}  (r0  <  d(r(-1)*x;y))  {}\mRightarrow{}  (|x\mcdot{}y|  <  (||x||  *  ||y||)))



Date html generated: 2017_10_03-AM-11_06_12
Last ObjectModification: 2017_03_02-PM-04_07_58

Theory : reals


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