10.03.2015 Views

v2009.01.01 - Convex Optimization

v2009.01.01 - Convex Optimization

v2009.01.01 - Convex Optimization

SHOW MORE
SHOW LESS

You also want an ePaper? Increase the reach of your titles

YUMPU automatically turns print PDFs into web optimized ePapers that Google loves.

136 CHAPTER 2. CONVEX GEOMETRY<br />

S = {s | s ≽ 0, 1 T s ≤ 1}<br />

1<br />

Figure 46: Unit simplex S in R 3 is a unique solid tetrahedron but not regular.<br />

A proper polyhedral cone in R n must have at least n linearly independent<br />

generators, or be the intersection of at least n halfspaces whose partial<br />

boundaries have normals that are linearly independent. Otherwise, the cone<br />

will contain at least one line and there can be no vertex; id est, the cone<br />

cannot otherwise be pointed.<br />

Examples of pointed closed convex cones K are not limited to polyhedral<br />

cones: the origin, any 0-based ray in a subspace, any two-dimensional<br />

V-shaped cone in a subspace, the Lorentz (ice-cream) cone and its polyhedral<br />

flavors, the cone of Euclidean distance matrices EDM N in S N h , the proper<br />

cones: S M + in ambient S M , any orthant in R n or R m×n ; e.g., the nonnegative<br />

real line R + in vector space R .

Hooray! Your file is uploaded and ready to be published.

Saved successfully!

Ooh no, something went wrong!