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: ^n rless: x < y rabs: |x| req: y rmul: b int-to-real: r(n) nat: all: x:A. B[x] implies:  Q minus: -n natural_number: $n
Definitions unfolded in proof :  all: x:A. B[x] implies:  Q member: t ∈ T uall: [x:A]. B[x] uimplies: supposing a and: P ∧ Q prop: subtype_rel: A ⊆B nat: le: A ≤ B less_than': less_than'(a;b) false: False not: ¬A iff: ⇐⇒ Q rev_implies:  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: y cand: c∧ B nat_plus: + 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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