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Generell informasjon
Postadresse:
Matematisk institutt
Universitetet i Oslo
Pb. 1053 Blindern
0316 Oslo
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Telefon og epost:
Tlf: 22 85 72 17 (kontor)
Tlf: 22 85 58 88 (sentralbord)
Fax: 22 85 43 49
E-mail: arnfinnl at math.uio.no
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Institusjonenes webadresse:
Universitetet i Oslo: www.uio.no
Matematisk institutt, UiO: www.math.uio.no
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Ovenbakken 16 c
1361 Østerås
Tlf: 67 14 39 31
Mobil: 48 12 24 57
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Aktuelt
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Forskning
I have, for most of my life, been interested in deformation
theory. This fascinating theory, first tuched upon by Bernhard Riemann,
holds that a mathematical object contains all the information needed to construct
the space of all iso-classes of "nearby" objects, and, in particular, all
the moduli, i.e. the parameters necessary to controle all infinitesimal
changes of the object.
This theory is the basis for the theory of moduli, in algebraic and analytic geometry.
However, treating moduli problems in general one
quickly runs into problems in classical algebraic geometry. It is f.ex.
difficult, or hopeless, to asssign to two orbits of a Lie-group, one
sitting in the closure of the other, two different points of a genuine
"space".
Here is where non-commutative algebraic geometry comes to the
rescue. In non-commutative theory, different points, infinitelyI close, exist,
and will be linked by a tangent. This is what non-commutative
deformation theory tells us, and using this construction, I propose a
non-commutative algebraic geometry, where points exist, and where moduli problems
in classical algebraic geometry, left open for a long time, have a solution.
The construction of non-commutative moduli spaces, like phase spaces in
physics, turns also out to give new insights in the relationship between
relativity theory and quantum theory.
This idea, and its "realization", has been my main interest the last 10
years. I am, today, convinced that the main tool of physics should be the
mathematical notion of moduli, in the non-commutative version hinted to
above, and that the crucial point is to define time as a "metric" on the
relevant moduli space. See the popular texts ...., and the papers ...
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Forskningsområder:
I have, in very early years, been interested in homological algebra, in
particular in the notions of projective and inductive limits, and in
spectral sequences. This led me to work on valuations, and on cohomology
theory for algebras and groups.
Later on I got involved in deformation theory, for commutative algebras, and
globally for schemes, see Springer Lecture Notes 754. An easy application of deformation theory
turned out to give a result on how curves cuts hyperplanes ("Laudal's lemma"), and this led to some
papers on algebraic geometry. In particular I worked, with Knud Lønsted, on
the moduli space of hyperelliptic curves.
Later on, and as a result of this study, I turned to singularities. The
main paper here is the Springer Lecture Notes 1083, with Pfister. As a
natural extension of this study, i worked for some time on deformations of
Lie algebras, and produced together with Harald Bjar a paper on the relationship
between the moduli space of isolated curve singularities and the
corresponding moduli space of Lie algebras of the automorphism groups.
Realizing that the theory of moduli for mathematical objects, like singularities and Lie
algebras, could not be adequately developed within classical algebraic
geometry, I turned to non-commutative geometry. First I constructed a
non-commutative deformation theory, and later extended this to a
non-commutative algebraic geometry.
The last years I have been working on mathematical physics, within this
non-commutative algebraic geometry, see latest papers, and the point above.
(til toppen av siden)
Publikasjoner
Some papers on homological algebra, algebraic geometry,
deformation theory and singularities.
- Sur la limite projective et la theorie de la dimension. I&II.
Seminaire Ehresmann, Paris 1961.
Sur les limites projectives et inductives.
Ann.Sci.Ecole Normale Sup., Paris t.82. 1965.
Projective systems on trees and valuation theory.
Canadian J. of Math. vol.20, 1968.
A generalized tri-secant lemma.
Algebraic Geometry.Proceedings Tromsø 1977,
Lecture Notes in Mathematics, Springer Verlag no.687.
Formal moduli of algebraic structures.
Lecture Notes in Mathematics no.754, Springer Verlag, 1979.(monograph)
Betti numbers of monoid algebras. Application to 2-dimensional torus
embeddings. (with A.B.Slettsjøe)
Math. Scand. 56 (1985) pp. 145-162
Matric Massey products and formal moduli.
Algebra, algebraic topology and their interactions.
Lecture Notes in Mathematics no.1183, Springer Verlag 1986.
(with G.Pfister) Local Moduli and Singularities.
Lecture Notes in Mathematics no.1310, Springer Verlag 1988.(monograph)
(with H.Bjar) Deformations of Lie algebras and Lie algebras of deformations.
Comp. Math.75: pp.69-111,1990.
A canonical stratification of the moduli of isolated
hypersurface singularities. Congres Singularites, Lille, 1991
(with Bjørn Jahren) The Sophus Lie Memorial Conference, Oslo 1992.Proceedings,
Scandinavian University Press, 1994.
Non commutative deformations of modules.
Preprint Series Inst. of Mathematics, University of Oslo,
No.2. pp.1-35, January 1995.
A generalized Burnside Theorem.
Preprint Series,University of Oslo, Institute of Mathematics,
No. 42,October 1995.
Noncommutative algebraic geometry.
Preprint Series,University of Oslo, Institute of Mathematics,
No.28, December 1996.
Non-commutative Algebraic Geometry.
Max-Planck-Institut fur Mathematik,Preprint Series no. 115, (2000).
Noncommutative Algebraic Geometry.
Proceedings of the International Conference in honor of Prof. Jose Luis
Vicente Cordoba, Sevilla 2001. Revista Matematica Iberamericana, 19 (2003).
Noncommutative deformations of modules.
Special Issue in Honor of JaErik Roos, Homology, Homotopy, and
Applications, Ed. Hvedri Inassaridze. International Press, (2002).
Homology, Homotopy, All. 4 (2002), pp. 357-396.
(with R.Piene) The Legacy of Niels Henrik Abel. The Abel Bicentennial,
Oslo, 2002. Springer-Verlag.(2004),ISBN 3-540-43826-2.
Noncom.def-quadr.forms.pdf .
The structure of Simp(A). Proceedings
of NATO Advanced Research Workshop, Computational Commutative and
Noncommutative Algebraic Geometry. Chisinau, Moldova, June 2004. .
Ph.ML.pdf .
Time-space and space-time. Conference on
Noncommutative Geometry and Representation Theory in Mathematical Physics.
Karlstad, 5-10 July 2004. Ed. Jurgen Fuchs, et al. American Mathematical
Society, Contemporary Mathematics, Vol. 391, 2005..
Geometry of Time-spaces I .
Geometry of Time-Spaces II .
Lahore p-groups .
Cosmos and its Furniture
Some papers on general subjects
Utarmet Uran. Rollelisten i spillet om bruk
av radioaktivt materiale i våpenindustrien..
Niels Henrik Abel. Review of the book of
A. Stubhaug..
Tid-rom og rom-tid. I red. Jan-Kyrre Berg Olsen: tid-fysiske, filosofiske og
videnskabsteoretiske perspektiver. Bifolia, (2003), pp. 45-65. ISBN:87-91319-09-9.
Om å forsvare sine helter..
Abels Paris Memoir..
CAS/SHS 1992-2002.
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