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Small deviations of gaussian random fields in lq–spaces. / Lifshits, Mikhail; Linde, Werner; Shi, Zhan.
In: Electronic Journal of Probability, Vol. 11, 01.01.2006, p. 1204-1233.Research output: Contribution to journal › Article › peer-review
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TY - JOUR
T1 - Small deviations of gaussian random fields in lq–spaces
AU - Lifshits, Mikhail
AU - Linde, Werner
AU - Shi, Zhan
PY - 2006/1/1
Y1 - 2006/1/1
N2 - We investigate small deviation properties of Gaussian random fields in the space Lq(ℝN, μ) where μ is an arbitrary finite compactly supported Borel measure. Of special interest are hereby “thin” measures μ, i.e., those which are singular with respect to the N–dimensional Lebesgue measure; the so–called self–similar measures providing a class of typical examples. For a large class of random fields (including, among others, fractional Brownian motions), we describe the behavior of small deviation probabilities via numerical characteristics of μ, called mixed entropy, characterizing size and regularity of μ. For the particularly interesting case of self–similar measures μ, the asymptotic behavior of the mixed entropy is evaluated explicitly. As a consequence, we get the asymptotic of the small deviation for N–parameter fractional Brownian motions with respect to Lq(ℝN, μ)– norms. While the upper estimates for the small deviation probabilities are proved by purely probabilistic methods, the lower bounds are established by analytic tools concerning Kolmogorov and entropy numbers of Hölder operators.
AB - We investigate small deviation properties of Gaussian random fields in the space Lq(ℝN, μ) where μ is an arbitrary finite compactly supported Borel measure. Of special interest are hereby “thin” measures μ, i.e., those which are singular with respect to the N–dimensional Lebesgue measure; the so–called self–similar measures providing a class of typical examples. For a large class of random fields (including, among others, fractional Brownian motions), we describe the behavior of small deviation probabilities via numerical characteristics of μ, called mixed entropy, characterizing size and regularity of μ. For the particularly interesting case of self–similar measures μ, the asymptotic behavior of the mixed entropy is evaluated explicitly. As a consequence, we get the asymptotic of the small deviation for N–parameter fractional Brownian motions with respect to Lq(ℝN, μ)– norms. While the upper estimates for the small deviation probabilities are proved by purely probabilistic methods, the lower bounds are established by analytic tools concerning Kolmogorov and entropy numbers of Hölder operators.
KW - Fractal measures
KW - Fractional Brownian motion
KW - Gaussian processes
KW - Hölder operators
KW - Kolmogorov numbers
KW - Metric entropy
KW - Random fields
KW - Self–similar measures
KW - Small deviations
UR - http://www.scopus.com/inward/record.url?scp=33845425130&partnerID=8YFLogxK
U2 - 10.1214/EJP.v11-379
DO - 10.1214/EJP.v11-379
M3 - Article
AN - SCOPUS:33845425130
VL - 11
SP - 1204
EP - 1233
JO - Electronic Journal of Probability
JF - Electronic Journal of Probability
SN - 1083-6489
ER -
ID: 37011503