| 1. |
- Ericsson, Niklas, 1968
(författare)
-
A Framework for Approximation of the Stokes Equations in an Axisymmetric Domain
- 2021
-
Ingår i: Computational Methods in Applied Mathematics. - : Walter de Gruyter GmbH. - 1609-4840 .- 1609-9389. ; 21:4
-
Tidskriftsartikel (refereegranskat)abstract
- We develop a framework for solving the stationary, incompressible Stokes equations in an axisymmetric domain. By means of Fourier expansion with respect to the angular variable, the three-dimensional Stokes problem is reduced to an equivalent, countable family of decoupled two-dimensional problems. By using decomposition of three-dimensional Sobolev norms, we derive natural variational spaces for the two-dimensional problems, and show that the variational formulations are well-posed. We analyze the error due to Fourier truncation and conclude that, for data that are sufficiently regular, it suffices to solve a small number of two-dimensional problems. © 2021 Ericsson, published by De Gruyter 2021.
|
|
| 2. |
- Lundström, Patrik, 1971-
(författare)
-
Self-dual Normal Integral Bases for Infinite Unramified Extensions
- 2002
-
Ingår i: Journal of Number Theory. - 0022-314X .- 1096-1658. ; 97:2, s. 350-367
-
Tidskriftsartikel (refereegranskat)abstract
- We prove a generalization to infinite Galois extensions of local fields, of a classical result by Noether on the existence of normal integral bases for finite tamely ramified Galois extensions. We also prove a self-dual normal integral basis theorem for infinite unramified Galois field extensions of local fields with finite residue fields of characteristic different from 2. This generalizes a result by Fainsilber for the finite case. To do this, we obtain an injectivity result concerning pointed cohomology sets, defined by inverse limits of norm-one groups of free finite-dimensional algebras with involution over complete discrete valuation rings.
|
|
| 3. |
|
|
| 4. |
- Lundström, Patrik, 1971-
(författare)
-
Generalized Brauer Algebras
- 2002
-
Ingår i: Communications in Algebra. - 0092-7872 .- 1532-4125. ; 30:5, s. 2229-2270
-
Tidskriftsartikel (refereegranskat)abstract
- Using some ideas of Brauer, we introduce what we call generalized Brauer algebras and, as a special case, Brauer orders. We show that many well-known classes of so-called crossed product algebras, and in particular, the well-known crossed product orders, can be obtained as special instances of our construction. We prove several results showing when Brauer orders are Azumaya, maximal, hereditary or Gorenstein.
|
|
| 5. |
|
|
| 6. |
|
|
| 7. |
|
|
| 8. |
- Lindström, David
(författare)
-
Evaluation of a Surrogate Based Method for Global Optimization
- 2015
-
Ingår i: International Journal of Computer, Electrical, Automation, Control and Information Engineering. - : World Academy of Science, Engineering and Technology. - 1307-6892. ; 9:7, s. 1636-1642
-
Tidskriftsartikel (refereegranskat)abstract
- We evaluate the performance of a numerical method for global optimization of expensive functions. The method is using a response surface to guide the search for the global optimum. This metamodel could be based on radial basis functions, kriging, or a combination of different models. We discuss how to set the cyclic parameters of the optimization method to get a balance between local and global search. We also discuss the eventual problem with Runge oscillations in the response surface.
|
|
| 9. |
- Lundström, Patrik, 1971-
(författare)
-
Von Neumann finite endomorphism rings
- 2003
-
Ingår i: Indagationes mathematicae. - Trollhättan : Högskolan Trollhättan/Uddevalla. - 0019-3577 .- 1872-6100. ; 14, s. 223-232
-
Tidskriftsartikel (refereegranskat)
|
|
| 10. |
- Nystedt, Patrik, 1971-
(författare)
-
Arc length of function graphs via Taylor’s formula
- 2021
-
Ingår i: International Journal of Mathematical Education in Science and Technology. - 0020-739X .- 1464-5211. ; 52:2, s. 310-323
-
Tidskriftsartikel (refereegranskat)abstract
- We use Taylor’s formula with Lagrange remainder to prove that functions with bounded second derivative are rectifiable in the case when polygonal paths are defined by interval subdivisions which are equally spaced. As a means for generating interesting examples of exact arc length calculations in calculus courses, we recall two large classes of functions f with the property that (Formula presented.) has a primitive, including classical examples by Neile, van Heuraet and Fermat, as well as more recent ones induced by Pythagorean triples of functions. We also discuss potential benefits for our proposed definition of arc length in introductory calculus courses. © 2020, © 2020 The Author(s). Published by Informa UK Limited, trading as Taylor & Francis Group.
|
|
