Nuprl Lemma : rv-pos-angle-permute-lemma

n:ℕ. ∀x,y:ℝ^n.  ((|x⋅y| < (||x|| ||y||))  (|x⋅x| < (||x|| ||y x||)))


Proof




Definitions occuring in Statement :  real-vec-norm: ||x|| dot-product: x⋅y real-vec-sub: Y real-vec: ^n rless: x < y rabs: |x| rmul: b nat: all: x:A. B[x] implies:  Q
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 nat_plus: + less_than: a < b squash: T less_than': less_than'(a;b) true: True prop: nat: le: A ≤ B false: False not: ¬A iff: ⇐⇒ Q rev_implies:  Q rsub: y
Lemmas referenced :  square-rless-implies rabs_wf dot-product_wf real-vec-sub_wf rmul_wf real-vec-norm_wf rmul-nonneg-case1 real-vec-norm-nonneg rnexp-rless zero-rleq-rabs less_than_wf rless_wf real-vec_wf nat_wf rnexp_wf false_wf le_wf rnexp2-nonneg rless_functionality req_inversion rabs-rnexp req_transitivity rnexp-rmul rmul_functionality real-vec-norm-squared rabs-of-nonneg req_weakening rnexp2 rsub_wf dot-product-comm radd_wf int-to-real_wf rminus_wf dot-product-linearity1-sub rsub_functionality radd-ac radd_functionality radd_comm rminus-rminus radd-int rminus-as-rmul radd-assoc rmul-distrib2 rminus-radd rminus_functionality rmul_comm rmul-distrib rmul_over_rminus radd-preserves-rless radd-zero-both rmul-zero-both rmul-identity1
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 dependent_set_memberEquality natural_numberEquality sqequalRule imageMemberEquality baseClosed productElimination minusEquality addEquality addLevel levelHypothesis

Latex:
\mforall{}n:\mBbbN{}.  \mforall{}x,y:\mBbbR{}\^{}n.    ((|x\mcdot{}y|  <  (||x||  *  ||y||))  {}\mRightarrow{}  (|x\mcdot{}y  -  x|  <  (||x||  *  ||y  -  x||)))



Date html generated: 2017_10_03-AM-10_57_36
Last ObjectModification: 2017_03_02-AM-10_57_59

Theory : reals


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