Browsing UiS Brage by Author "Hervik, Sigbjørn"

Now showing items 1-20 of 29

    • A spacetime not characterized by its invariants is of aligned type II 

      Hervik, Sigbjørn (Journal article; Peer reviewed, 2011)
      By using invariant theory we show that a (higher-dimensional) Lorentzian metric that is not characterised by its invariants must be of aligned type II; i.e., there exists a frame such that all the curvature tensors ...

    • All metrics have curvature tensors characterised by its invariants as a limit: the ϵ-property 

      Hervik, Sigbjørn (Journal article; Peer reviewed, 2011)
      We prove a generalisation of the ϵ-property, namely that for any dimension and signature, a metric which is not characterised by its polynomial scalar curvature invariants, there is a frame such that the components of the ...

    • Curvature operators and scalar curvature invariants 

      Hervik, Sigbjørn; Coley, Alan (Journal article; Peer reviewed, 2010)
      We continue the study of the question of when a pseudo-Riemannain manifold can be locally characterised by its scalar polynomial curvature invariants (constructed from the Riemann tensor and its covariant deriva- tives). ...

    • Discriminating the Weyl type in higher dimensions using scalar curvature invariants 

      Hervik, Sigbjørn; Coley, Alan (Journal article; Peer reviewed, 2011)
      We consider higher dimensional Lorentzian spacetimes which are currently of interest in theoretical physics. It is possible to algebraically classify any tensor in a Lorentzian spacetime of arbitrary dimensions using ...

    • Dybdelæring i matematikk 

      Serigstad, Adrian (Master thesis, 2023)
      This study examines deep learning in mathematics and investigates whether a focus on deep learning can lead to deep understanding of a mathematical topic. Deep learning proves to be a diverse concept with various interpretations ...

    • Dybdelæring og tverrfaglighet 

      Østebø, Marlene Seljeskog; Urianstad, Simen Bugge (Master thesis, 2023)
      Da ny læreplan av 2020 ble introdusert, var det spesielt et begrep som stod i fokus - dybdelæring. Hvor tidligere læreplan ønsket at elevene skulle kunne utføre oppgaver gjennom en instrumentell forståelse, skulle elevene ...

    • Higher dimensional bivectors and classification of the Weyl operator 

      Hervik, Sigbjørn; Coley, Alan (Journal article; Peer reviewed, 2010)
      We develop the bivector formalism in higher dimensional Lorentzian spacetimes. We define the Weyl bivector operator in a manner consis- tent with its boost-weight decomposition. We then algebraically classify the Weyl ...

    • Inflation with stable anisotropic hair 

      Hervik, Sigbjørn; Mota, David F.; Thorsrud, Mikjel (Journal article; Peer reviewed, 2011)
      Recently an inflationary model with a vector field coupled to the inflaton was proposed and the phenomenology studied for the Bianchi type I spacetime. It was found that the model demonstrates a counter-example to the ...

    • Left-Invariant Pseudo-Riemannian Metrics on Lie Groups 

      Markestad, Styrbjørn Juhl (Masteroppgave/UIS-TN-IMF/2020;, Master thesis, 2020)
      n differential geometry and mathematical physics, there is interest in left-invariant pseudo-Riemannian metrics on Lie groups. We learn and review Lie theory, representation theory, geometric invariant theory, and differential ...

    • A mathematical approach to Wick rotations 

      Helleland, Christer (PhD thesis UiS;536, Doctoral thesis, 2020-09)
      In this thesis we define Wick-rotations mathematically using pseudo-Riemannian geometry, and relate Wick-rotations to real geometric invariant theory (GIT). We discover some new results concerning the existence of Wick ...

    • Nil-Killing vector fields and Kundt structures 

      Aadne, Matthew Terje (PhD thesis UiS;529, Doctoral thesis, 2020-06)
      This thesis is based on three papers, for which two have been submitted for publication and one is published. A chapter presenting relevant background material is included giving convenient access to preliminary foreknowledge ...

    • Note on the invariant classification of vacuum type D spacetimes 

      Coley, Alan; Hervik, Sigbjørn (Journal article; Peer reviewed, 2009-12)
      We illustrate the fact that the class of vacuum type D spacetimes which are I-non-degenerate are invariantly classified by their scalar polynomial curvature invariants.

    • On the algebraic classification of pseudo-Riemannian spaces 

      Hervik, Sigbjørn; Coley, Alan (Journal article; Peer reviewed, 2011-12)
      We consider arbitrary-dimensional pseudo-Riemannian spaces of signature (k, k + m). We introduce a boost-weight decomposition and define a number of algebraic properties (e.g. the Si- and N-properties) and present a ...

    • On Universal Black Holes 

      Hervik, Sigbjørn; Ortaggio, Marcello (Peer reviewed; Journal article, 2020)
      Recent results on universal black holes in d dimensions are summarized. These are static metrics with an isotropy-irreducible homogeneous base space which can be consistently employed to construct solutions to virtually ...

    • Open Middle Math og dybdelæring i Matematikk 

      Nesheim, Sigrunn Westersjø (Master thesis, 2022)
      Denne oppgaven trekker frem undervisningskonseptet Open Middle Math (Kaplinsky, Open Middle Math, 2020) og drøfter om dette konseptet bidrar til dybdelæring i matematikk. For å besvare dette spørsmålet er det gjennomført ...

    • "Open Middle Math" og dets bidrag til dybdelæring i matematikk 

      Seland, Didrik (Master thesis, 2022)
      Dette prosjektet baserer seg på Robert Kaplinskys (Kaplinsky, 2020) teori om «Open Middle Math», og har som mål å undersøke om undervisning med dette kan bidra til dybdelæring hos elever. I forbindelse med prosjektet ble ...

    • «Open Middle Math» og dets bidrag til undervisning i matematikk 

      Mølstre, Monica Emilie (Master thesis, 2021)
      I denne masteroppgaven er det foretatt innhenting av datamateriale gjennom elevers oppgaveløsning i rammeverket «Open Middle Math». Målet ved observasjon og utprøving av oppgavetypen har vært å se om det kan være et godt ...

    • «Open Middle Math», dybdelæring & positive holdninger i matematikk 

      Ramstad, Sunniva Fosnes (Masteroppgave/UIS-HF-IMF/2020;, Master thesis, 2019-07)
      Som både lektorstudent og deltidsarbeidene i videregående skole er det mye fokus på hvordan lærere skal forberede seg i møte med fagfornyelsen. Dybdelæring er et sentralt begrep i fagfornyelsen. Motivasjonen for denne ...

    • Pseudo-Riemannian VSI spaces 

      Hervik, Sigbjørn; Coley, Alan (Journal article; Peer reviewed, 2011)
      In this paper we consider pseudo-Riemannian spaces of arbitrary sig- nature for which all of their polynomial curvature invariants vanish (VSI spaces). We discuss an algebraic classification of pseudo-Riemannian spaces ...

    • Pseudo-Riemannian VSI spaces II 

      Hervik, Sigbjørn (Journal article; Peer reviewed, 2012)
      In this paper we consider pseudo-Riemannian spaces of arbitrary signature for which all of the polynomial curvature invariants vanish (VSI spaces). Using an algebraic classification of pseudo-Riemannian spaces in terms of ...