Change search
Refine search result
1 - 5 of 5
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Rows per page
  • 5
  • 10
  • 20
  • 50
  • 100
  • 250
Sort
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
Select
The maximal number of hits you can export is 250. When you want to export more records please use the Create feeds function.
  • 1. Ibragimov, N. H.
    et al.
    Kolsrud, Torbjörn
    KTH, Superseded Departments, Mathematics.
    Lagrangian approach to evolution equations: Symmetries and conservation laws2004In: Nonlinear dynamics, ISSN 0924-090X, E-ISSN 1573-269X, Vol. 36, no 1, p. 29-40Article in journal (Refereed)
    Abstract [en]

    We show that one can apply a Lagrangian approach to certain evolution equations by considering them together with their associated equations. Consequently, one can employ Noether's theorem and derive conservation laws from symmetries of coupled systems of evolution equations. We discuss in detail the linear and non-linear heat equations as well as the Burgers equation and obtain new non-local conservation laws for the non-linear heat and the Burgers equations by extending their symmetries to the associated equations. We also provide Lagrangians for non-linear Schrodinger and Korteweg-de Vries type systems.

  • 2. Iwata, Koichiro
    et al.
    Kolsrud, Torbjörn
    KTH, School of Engineering Sciences (SCI), Mathematics (Dept.), Mathematics (Div.).
    Central limit theorem for constrained Poisson systems2009In: Bulletin des Sciences Mathématiques, ISSN 0007-4497, E-ISSN 1952-4773, Vol. 133, no 6, p. 658-669Article in journal (Refereed)
    Abstract [en]

    We prove that for a class of constrained Poisson white noise fields. the scaling (continuum) limit exists and equals Gaussian white noise. indexed by mean zero test functions. Under natural conditions on the Levy measure, the (Poisson) moments converge to their Gaussian counterparts.

  • 3.
    Kolsrud, Torbjörn
    KTH, School of Engineering Sciences (SCI), Mathematics (Dept.), Mathematics (Div.).
    Position dependent non-linear Schrodinger hierarchies: Involutivity, commutation relations, renormalisation and classical invariants2006In: Bulletin des Sciences Mathématiques, ISSN 0007-4497, E-ISSN 1952-4773, Vol. 130, no 8, p. 739-756Article in journal (Refereed)
    Abstract [en]

    We consider a family of explicitly position dependent hierarchies (I-n)(0)(infinity), containing the NLS (non-linear Schrodinger) hierarchy. All (I-n)(0)(infinity) are involutive and fulfill DIn = nI(n-1), where D = D-1 V-0, V-0 being the Hamiltonian vector field v delta/delta v - u delta/delta u afforded by the common ground state I-0 = uv. The construction requires renormalisation of certain function parameters. It is shown that the 'quantum space' C[I-0, I-1,...] projects down to its classical counterpart C[p], with p = I-1/I-0, the momentum density. The quotient is the kernel of D. It is identified with classical semi-invariants for forms in two variables.

  • 4.
    Kolsrud, Torbjörn
    KTH, School of Engineering Sciences (SCI), Mathematics (Dept.).
    Quantum and classical conserved quantities: Martingales, conservation laws and constants of motion2007In: Stochastic Analysis and Applications / [ed] Benth, FE; DiNunno, G; Lindstrom, T; Oksendal, B; Zhang, T, 2007, Vol. 2, p. 461-491Conference paper (Refereed)
    Abstract [en]

    We study a class of diffusions, conjugate Brownian motion, related to Brownian motion in Riemannian manifolds. Mappings that, up to a change of time scale, carry these processes into each other, are characterised. The characterisation involves conformality and a space-time version of harmonicity. Infinitesimal descriptions are given and used to produce martingales and conservation laws. The relation to classical constants of motion is presented, as well as the relation to Noether's theorem in classical mechanics and field theory.

  • 5.
    Kolsrud, Torbjörn
    et al.
    KTH, Superseded Departments, Mathematics.
    Loubeau, E.
    Foliated manifolds and conformal heat morphisms2002In: Annals of Global Analysis and Geometry, ISSN 0232-704X, E-ISSN 1572-9060, Vol. 21, no 3, p. 241-267Article in journal (Refereed)
    Abstract [en]

    The objects under study, in this article, are Riemannian manifolds foliated by hypersurfaces. Looking at the transverse direction as time, we construct the generalised heat operator and, in the spirit of a time-space extension of harmonic morphisms, we introduce the conformal heat morphisms. Concrete examples of these concepts are presented, as well as, a characterisation of conformal heat morphisms. Lastly, we calculate the heat Lie algebra of the generalised heat operator.

1 - 5 of 5
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf