Nuprl Lemma : rv-norm-triangle-inequality2
∀[rv:InnerProductSpace]. ∀[x,y,z:Point].  (||x - z|| ≤ (||x - y|| + ||y - z||))
Proof
Definitions occuring in Statement : 
rv-norm: ||x||
, 
rv-sub: x - y
, 
inner-product-space: InnerProductSpace
, 
ss-point: Point
, 
rleq: x ≤ y
, 
radd: a + b
, 
uall: ∀[x:A]. B[x]
Definitions unfolded in proof : 
rv-sub: x - y
, 
uiff: uiff(P;Q)
, 
rge: x ≥ y
, 
rev_uimplies: rev_uimplies(P;Q)
, 
uimplies: b supposing a
, 
guard: {T}
, 
prop: ℙ
, 
subtype_rel: A ⊆r B
, 
false: False
, 
implies: P 
⇒ Q
, 
not: ¬A
, 
and: P ∧ Q
, 
le: A ≤ B
, 
all: ∀x:A. B[x]
, 
rnonneg: rnonneg(x)
, 
rleq: x ≤ y
, 
member: t ∈ T
, 
uall: ∀[x:A]. B[x]
Lemmas referenced : 
rv-0-add, 
rv-add-minus, 
rv-add_functionality, 
ss-eq_inversion, 
ss-eq_transitivity, 
uiff_transitivity, 
rv-add-assoc, 
ss-eq_functionality, 
ss-eq_weakening, 
rv-0_wf, 
ss-eq_wf, 
rv-add-cancel-right, 
rv-minus_wf, 
rv-norm_functionality, 
req_weakening, 
rleq_functionality, 
rv-norm-triangle-inequality, 
rleq_weakening_equal, 
rleq_functionality_wrt_implies, 
rv-add_wf, 
separation-space_wf, 
real-vector-space_wf, 
inner-product-space_wf, 
subtype_rel_transitivity, 
real-vector-space_subtype1, 
ss-point_wf, 
nat_plus_wf, 
rv-ip_wf, 
rmul_wf, 
req_wf, 
int-to-real_wf, 
rleq_wf, 
real_wf, 
inner-product-space_subtype, 
rv-sub_wf, 
rv-norm_wf, 
radd_wf, 
rsub_wf, 
less_than'_wf
Rules used in proof : 
independent_functionElimination, 
voidElimination, 
isect_memberEquality, 
independent_isectElimination, 
instantiate, 
equalitySymmetry, 
equalityTransitivity, 
axiomEquality, 
minusEquality, 
natural_numberEquality, 
productEquality, 
setEquality, 
rename, 
setElimination, 
hypothesis, 
applyEquality, 
isectElimination, 
extract_by_obid, 
because_Cache, 
independent_pairEquality, 
productElimination, 
hypothesisEquality, 
thin, 
dependent_functionElimination, 
lambdaEquality, 
sqequalHypSubstitution, 
sqequalRule, 
cut, 
introduction, 
isect_memberFormation, 
sqequalReflexivity, 
computationStep, 
sqequalTransitivity, 
sqequalSubstitution
Latex:
\mforall{}[rv:InnerProductSpace].  \mforall{}[x,y,z:Point].    (||x  -  z||  \mleq{}  (||x  -  y||  +  ||y  -  z||))
Date html generated:
2016_11_08-AM-09_17_31
Last ObjectModification:
2016_11_01-PM-05_50_51
Theory : inner!product!spaces
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