Zobrazeno 1 - 10
of 90
pro vyhledávání: '"Kaj Nyström"'
Autor:
Prashanta Garain, Kaj Nyström
Publikováno v:
Mathematics in Engineering, Vol 5, Iss 2, Pp 1-37 (2023)
We consider nonlinear Kolmogorov-Fokker-Planck type equations of the form $ \begin{equation*} (\partial_t+X\cdot\nabla_Y)u = \nabla_X\cdot(A(\nabla_X u, X, Y, t)). \end{equation*} $ The function $ A = A(\xi, X, Y, t): \mathbb R^m\times \mathbb R^
Externí odkaz:
https://doaj.org/article/d1b4195e971b44edbb30035bb7de6ec3
Autor:
Malte Litsgård, Kaj Nyström
Publikováno v:
Journal de Mathématiques Pures et Appliquées. 157:45-100
In this paper we develop a potential theory for strongly degenerate parabolic operators of the form L : = ∇ X ⋅ ( A ( X , Y , t ) ∇ X ) + X ⋅ ∇ Y − ∂ t , in unbounded domains of the form Ω = { ( X , Y , t ) = ( x , x m , y , y m , t )
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_dedup___::18910ff5018acf770ffd403f9a843f4b
https://doi.org/10.1016/j.matpur.2021.11.004
https://doi.org/10.1016/j.matpur.2021.11.004
The fractional heat operator (& part;(t )- delta(x))(s) and Continuous Time Random Walks (CTRWs) are interesting and sophisticated mathematical models that can describe complex anomalous systems. In this paper, we prove asymptotic mean value represen
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_dedup___::faba429259f2e2807dce60b450b9ae77
http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-486598
http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-486598
Autor:
Kaj Nyström, Changyong Zhang
Publikováno v:
Journal of the Operational Research Society. 73:2168-2185
Compared with low frequency data, high frequency data exhibit distinct empirical properties, including, for instance, essentially discontinuous evolution paths, time-varying intensities, and self-e...
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_________::984a16c8f9f03b9957d09b341132917e
https://doi.org/10.1080/01605682.2021.1952116
https://doi.org/10.1080/01605682.2021.1952116
Publikováno v:
J. Eur. Math. Soc. (JEMS) 6
J. Eur. Math. Soc. (JEMS) 6, 2020, 22 (9), pp.2943--3058
Journal of the European Mathematical Society
Journal of the European Mathematical Society, European Mathematical Society, 2020, 22 (9), pp.2943-3058. ⟨10.4171/JEMS/980⟩
J. Eur. Math. Soc. (JEMS) 6, 2020, 22 (9), pp.2943--3058
Journal of the European Mathematical Society
Journal of the European Mathematical Society, European Mathematical Society, 2020, 22 (9), pp.2943-3058. ⟨10.4171/JEMS/980⟩
We prove the first positive results concerning boundary value problems in the upper half-space of second order parabolic systems only assuming measurability and some transversal regularity in the coefficients of the elliptic part. To do so, we introd
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_dedup___::0fe8c82be0f01d61b3d4b9064aac1f1d
https://doi.org/10.4171/jems/980
https://doi.org/10.4171/jems/980
We introduce a new class of strongly degenerate nonlinear parabolic PDEs ((p - 2)Delta(N)(infinity,X) + Delta(X))u(X, Y, t) + (m +p)(X . del(Yu)(X, Y, t) - partial derivative(t)u(X, Y, t)) = 0, (X, Y, t) is an element of R-m x R-m x R, p is an elemen
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_dedup___::6f064d201d570c9d64fcd5537fd9d309
http://arxiv.org/abs/2202.01012
http://arxiv.org/abs/2202.01012
We prove that coronizations with respect to arbitrary d-regular sets (not necessarily graphs) imply big pieces squared of these (approximating) sets. This is known (and due to David and Semmes in the case of sufficiently large co-dimension, and to Az
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_dedup___::67fb230c0c63b404bd127d14f62b1c39
http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-492118
http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-492118
Autor:
Prashanta Garain, Kaj Nyström
We consider nonlinear Kolmogorov-Fokker-Planck type equations of the form \begin{equation}\label{abeqn} (\partial_t+X\cdot\nabla_Y)u=\nabla_X\cdot(A(\nabla_X u,X,Y,t)). \end{equation} The function $A=A(\xi,X,Y,t):\R^m\times\R^m\times\R^m\times\R\to\R
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_dedup___::21b030d8a0dbc0126bff7c2cd8becb6e
Autor:
Carmina Fjellström, Kaj Nyström
Stochastic gradient descent (SGD) is widely used in deep learning due to its computational efficiency, but a complete understanding of why SGD performs so well remains a major challenge. It has been observed empirically that most eigenvalues of the H
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_dedup___::749c06d0e0bb9254530ad741e2df2e7b
http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-486599
http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-486599
Autor:
Malte Litsgård, Kaj Nyström
We consider fractional operators of the form $$\begin{aligned} {\mathcal {H}}^s=(\partial _t -\text {div}_{x} ( A(x,t)\nabla _{x}))^s,\ (x,t)\in {\mathbb {R}}^n\times {\mathbb {R}}, \end{aligned}$$ H s = ( ∂ t - div x ( A ( x , t ) ∇ x ) ) s , (
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_dedup___::35279dd77d6ab6c6ab00f132cfa50fa6
http://arxiv.org/abs/2104.07313
http://arxiv.org/abs/2104.07313