Nuprl Lemma : rv-pos-angle-permute-lemma
∀n:ℕ. ∀x,y:ℝ^n.  ((|x⋅y| < (||x|| * ||y||)) 
⇒ (|x⋅y - x| < (||x|| * ||y - x||)))
Proof
Definitions occuring in Statement : 
real-vec-norm: ||x||
, 
dot-product: x⋅y
, 
real-vec-sub: X - Y
, 
real-vec: ℝ^n
, 
rless: x < y
, 
rabs: |x|
, 
rmul: a * b
, 
nat: ℕ
, 
all: ∀x:A. B[x]
, 
implies: P 
⇒ Q
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
, 
nat_plus: ℕ+
, 
less_than: a < b
, 
squash: ↓T
, 
less_than': less_than'(a;b)
, 
true: True
, 
prop: ℙ
, 
nat: ℕ
, 
le: A ≤ B
, 
false: False
, 
not: ¬A
, 
iff: P 
⇐⇒ Q
, 
rev_implies: P 
⇐ Q
, 
rsub: x - 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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