Global Information Lookup Global Information

Strictly convex space information


The unit ball in the middle figure is strictly convex, while the other two balls are not (they contain a line segment as part of their boundary).

In mathematics, a strictly convex space is a normed vector space (X, || ||) for which the closed unit ball is a strictly convex set. Put another way, a strictly convex space is one for which, given any two distinct points x and y on the unit sphere ∂B (i.e. the boundary of the unit ball B of X), the segment joining x and y meets ∂B only at x and y. Strict convexity is somewhere between an inner product space (all inner product spaces being strictly convex) and a general normed space in terms of structure. It also guarantees the uniqueness of a best approximation to an element in X (strictly convex) out of a convex subspace Y, provided that such an approximation exists.

If the normed space X is complete and satisfies the slightly stronger property of being uniformly convex (which implies strict convexity), then it is also reflexive by Milman–Pettis theorem.

and 25 Related for: Strictly convex space information

Request time (Page generated in 0.8274 seconds.)

Strictly convex space

Last Update:

strictly convex space is a normed vector space (X, || ||) for which the closed unit ball is a strictly convex set. Put another way, a strictly convex...

Word Count : 304

Strictly convex

Last Update:

enclosing a strictly convex set of points Strictly convex set, a set whose interior contains the line between any two points Strictly convex space, a normed...

Word Count : 96

Convex function

Last Update:

properties. For instance, a strictly convex function on an open set has no more than one minimum. Even in infinite-dimensional spaces, under suitable additional...

Word Count : 5850

Convex set

Last Update:

In geometry, a subset of a Euclidean space, or more generally an affine space over the reals, is convex if, given any two points in the subset, the subset...

Word Count : 3037

Convex polygon

Last Update:

polygon is convex if every line that does not contain any edge intersects the polygon in at most two points. A strictly convex polygon is a convex polygon...

Word Count : 881

Uniformly convex space

Last Update:

In mathematics, uniformly convex spaces (or uniformly rotund spaces) are common examples of reflexive Banach spaces. The concept of uniform convexity...

Word Count : 612

Partially ordered set

Last Update:

said to be strictly less than an element b, if a ≤ b and a ≠ b . {\displaystyle a\neq b.} For example, { x } {\displaystyle \{x\}} is strictly less than...

Word Count : 5395

Quasiconvex function

Last Update:

\}}} A (strictly) quasiconvex function has (strictly) convex lower contour sets, while a (strictly) quasiconcave function has (strictly) convex upper contour...

Word Count : 1448

Logarithmically convex function

Last Update:

{\displaystyle {\log }\circ f} is convex, and Strictly logarithmically convex if log ∘ f {\displaystyle {\log }\circ f} is strictly convex. Here we interpret log...

Word Count : 988

Convex cone

Last Update:

open half-space uses strict inequality. Half-spaces (open or closed) are affine convex cones. Moreover (in finite dimensions), any convex cone C that...

Word Count : 3204

Convex curve

Last Update:

include the closed convex curves (the boundaries of bounded convex sets), the smooth curves that are convex, and the strictly convex curves, which have...

Word Count : 4154

Convex conjugate

Last Update:

\end{cases}}} The convex conjugate and Legendre transform of the exponential function agree except that the domain of the convex conjugate is strictly larger as...

Word Count : 2019

Convex polytope

Last Update:

n} -dimensional Euclidean space R n {\displaystyle \mathbb {R} ^{n}} . Most texts use the term "polytope" for a bounded convex polytope, and the word "polyhedron"...

Word Count : 3266

Concave function

Last Update:

a\}} are convex sets. A differentiable function f is (strictly) concave on an interval if and only if its derivative function f ′ is (strictly) monotonically...

Word Count : 1336

Sequence space

Last Update:

does not admit a strictly coarser Hausdorff, locally convex topology. For that reason, the study of sequences begins by finding a strict linear subspace...

Word Count : 3603

Topological vector space

Last Update:

locally convex. Banach spaces, Hilbert spaces and Sobolev spaces are other well-known examples of TVSs. Many topological vector spaces are spaces of functions...

Word Count : 13527

LogSumExp

Last Update:

x_{n}\}}.} The LogSumExp function is convex, and is strictly increasing everywhere in its domain. It is not strictly convex, since it is affine (linear plus...

Word Count : 1150

Reflexive space

Last Update:

mathematics known as functional analysis, a reflexive space is a locally convex topological vector space for which the canonical evaluation map from X {\displaystyle...

Word Count : 6405

Extreme point

Last Update:

In mathematics, an extreme point of a convex set S {\displaystyle S} in a real or complex vector space is a point in S {\displaystyle S} that does not...

Word Count : 2071

Modulus and characteristic of convexity

Last Update:

and the characteristic of convexity are measures of "how convex" the unit ball in a Banach space is. In some sense, the modulus of convexity has the same...

Word Count : 964

Monotonic function

Last Update:

concept called strictly decreasing (also decreasing). A function with either property is called strictly monotone. Functions that are strictly monotone are...

Word Count : 2467

Convex optimization

Last Update:

Convex optimization is a subfield of mathematical optimization that studies the problem of minimizing convex functions over convex sets (or, equivalently...

Word Count : 3092

List of regular polytopes

Last Update:

{5}, {5/2}, and {6}. Beyond Euclidean space, there is an infinite set of regular hyperbolic tilings. The five convex regular polyhedra are called the Platonic...

Word Count : 5294

Geodesic convexity

Last Update:

geodesically convex subset of M. A function f : C → R {\displaystyle f:C\to \mathbf {R} } is said to be a (strictly) geodesically convex function if the...

Word Count : 327

Convex analysis

Last Update:

≤) is replaced by the strict inequality then f {\displaystyle f} is called strictly convex. Convex functions are related to convex sets. Specifically, the...

Word Count : 2611

PDF Search Engine © AllGlobal.net