Entropy of convex hulls--some Lorentz norm results
نویسنده
چکیده
Let A be a subset of a type p Banach space E, 1 < p ≤ 2, such that its entropy numbers satisfy ( εn(A) ) n ∈ `q,s for some q, s ∈ (0,∞). We show ( en(acoA) ) n ∈ `r,s for the dyadic entropy numbers of the absolutely convex hull acoA of A, where r is defined by 1/r = 1/p′+1/q. Furthermore, we show for slowly decreasing entropy numbers that ( en(A) ) n ∈ `q,s implies ( en(acoA) ) n ∈ `p′,s for all 0 < s <∞ and q defined by 1/q = 1/p′ + 1/s. AMS classification: 41A46, 46B07, 46B20, 52A07
منابع مشابه
Gelfand numbers and metric entropy of convex hulls in Hilbert spaces
We establish optimal estimates of Gelfand numbers or Gelfand widths of absolutely convex hulls cov(K) of precompact subsets K ⊂ H of a Hilbert space H by the metric entropy of the set K where the covering numbers N(K, ") of K by "-balls of H satisfy the Lorentz condition ∫ ∞ 0 ( log2N(K, ") )r/s d" <∞ for some fixed 0 < r, s ≤ ∞ with the usual modifications in the cases r = ∞, 0 < s < ∞ and 0 <...
متن کاملEntropy of Absolute Convex Hulls in Hilbert Spaces
The metric entropy of absolute convex hulls of sets in Hilbert spaces is studied for the general case when the metric entropy of the sets is arbitrary. Under some regularity assumptions, the results are sharp.
متن کاملGeometric parameters in Learning Theory
3 Uniform measures of complexity 12 3.1 Metric entropy and the combinatorial dimension . . . . . . . . . 12 3.1.1 Binary valued classes . . . . . . . . . . . . . . . . . . . . . 13 3.1.2 Real valued classes . . . . . . . . . . . . . . . . . . . . . . 15 3.2 Random averages and the combinatorial dimension . . . . . . . . 17 3.3 Phase transitions in GC classes . . . . . . . . . . . . . . . . . . ...
متن کاملAdaptive (Analysis of) Algorithms for Convex Hulls and Related Problems
Adaptive analysis is a well known technique in computational geometry, which re nes the traditional worst case analysis over all instances of xed input size by taking into account some other parameters, such as the size of the output in the case of output sensitive analysis. We present two adaptive techniques for the computation of the convex hull in two and three dimensions and related problem...
متن کاملMetric Entropy of Convex Hulls
Let T be a precompact subset of a Hilbert space. The metric entropy of the convex hull of T is estimated in terms of the metric entropy of T , when the latter is of order α = 2. The estimate is best possible. Thus, it answers a question left open in [LL] and [CKP]. 0.
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید
ثبت ناماگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید
ورودعنوان ژورنال:
- Journal of Approximation Theory
دوره 128 شماره
صفحات -
تاریخ انتشار 2004