Nuprl Lemma : Minkowski-equality
∀n:ℕ. ∀x,y:ℝ^n.
  ((r0 < ||y||) ⇒ (||x + y|| = (||x|| + ||y||)) ⇒ (∃t:ℝ. ((r0 ≤ t) ∧ req-vec(n;x;t*y) ∧ ((r0 < ||x||) ⇒ (r0 < t)))))
Proof
Definitions occuring in Statement : 
real-vec-norm: ||x||, 
real-vec-mul: a*X, 
real-vec-add: X + Y, 
req-vec: req-vec(n;x;y), 
real-vec: ℝ^n, 
rleq: x ≤ y, 
rless: x < y, 
req: x = y, 
radd: a + b, 
int-to-real: r(n), 
real: ℝ, 
nat: ℕ, 
all: ∀x:A. B[x], 
exists: ∃x:A. B[x], 
implies: P ⇒ Q, 
and: P ∧ Q, 
natural_number: $n
Definitions unfolded in proof : 
all: ∀x:A. B[x], 
implies: P ⇒ Q, 
member: t ∈ T, 
uall: ∀[x:A]. B[x], 
nat: ℕ, 
le: A ≤ B, 
and: P ∧ Q, 
less_than': less_than'(a;b), 
false: False, 
not: ¬A, 
prop: ℙ, 
itermConstant: "const", 
req_int_terms: t1 ≡ t2, 
top: Top, 
uiff: uiff(P;Q), 
uimplies: b supposing a, 
rev_uimplies: rev_uimplies(P;Q), 
rneq: x ≠ y, 
guard: {T}, 
or: P ∨ Q, 
iff: P ⇐⇒ Q, 
rev_implies: P ⇐ Q, 
less_than: a < b, 
squash: ↓T, 
true: True, 
exists: ∃x:A. B[x], 
cand: A c∧ B, 
rdiv: (x/y)
Lemmas referenced : 
rnexp-positive, 
real-vec-norm_wf, 
false_wf, 
le_wf, 
req_wf, 
real-vec-add_wf, 
radd_wf, 
rless_wf, 
int-to-real_wf, 
real-vec_wf, 
nat_wf, 
rnexp_wf, 
dot-product_wf, 
rmul_wf, 
dot-product-comm, 
real_term_polynomial, 
itermSubtract_wf, 
itermAdd_wf, 
itermVar_wf, 
itermMultiply_wf, 
itermConstant_wf, 
real_term_value_const_lemma, 
real_term_value_sub_lemma, 
real_term_value_add_lemma, 
real_term_value_var_lemma, 
real_term_value_mul_lemma, 
req-iff-rsub-is-0, 
req_functionality, 
req_transitivity, 
real-vec-norm-squared, 
dot-product-linearity1, 
radd_functionality, 
req_weakening, 
rmul_functionality, 
radd-preserves-req, 
rminus_wf, 
rnexp_functionality, 
rnexp2, 
itermMinus_wf, 
real_term_value_minus_lemma, 
rmul_preserves_req, 
rless-int, 
req_inversion, 
rabs_wf, 
rmul-nonneg-case1, 
real-vec-norm-nonneg, 
rabs-of-nonneg, 
rleq_functionality, 
rdiv_wf, 
rmul_preserves_rleq, 
rmul_preserves_rless, 
rleq_wf, 
req-vec_wf, 
real-vec-mul_wf, 
rinv_wf2, 
rmul-rinv, 
rless_functionality, 
rmul-is-positive
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
lambdaFormation, 
cut, 
introduction, 
extract_by_obid, 
sqequalHypSubstitution, 
dependent_functionElimination, 
thin, 
isectElimination, 
hypothesisEquality, 
hypothesis, 
independent_functionElimination, 
dependent_set_memberEquality, 
natural_numberEquality, 
sqequalRule, 
independent_pairFormation, 
because_Cache, 
computeAll, 
lambdaEquality, 
int_eqEquality, 
intEquality, 
isect_memberEquality, 
voidElimination, 
voidEquality, 
productElimination, 
independent_isectElimination, 
inrFormation, 
imageMemberEquality, 
baseClosed, 
dependent_pairFormation, 
productEquality, 
functionEquality, 
inlFormation
Latex:
\mforall{}n:\mBbbN{}.  \mforall{}x,y:\mBbbR{}\^{}n.
    ((r0  <  ||y||)
    {}\mRightarrow{}  (||x  +  y||  =  (||x||  +  ||y||))
    {}\mRightarrow{}  (\mexists{}t:\mBbbR{}.  ((r0  \mleq{}  t)  \mwedge{}  req-vec(n;x;t*y)  \mwedge{}  ((r0  <  ||x||)  {}\mRightarrow{}  (r0  <  t)))))
 Date html generated: 
2017_10_03-AM-10_55_22
 Last ObjectModification: 
2017_07_28-AM-08_20_58
Theory : reals
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