Tidligere arrangementer - Side 21
Phase tropical surfaces can appear as a limit of a 1-parameter family of smooth complex algebraic surfaces. A phase tropical surface admits a stratified fibration over a smooth tropical surface. We study the real structures compatible with this fibration and give a description in terms of tropical cohomology. As an application, we deduce combinatorial criteria for the type of a real structure of a phase tropical surface.
Phase tropical surfaces can appear as a limit of a 1-parameter family of smooth complex algebraic surfaces. A phase tropical surface admits a stratified fibration over a smooth tropical surface. We study the real structures compatible with this fibration and give a description in terms of tropical cohomology. As an application, we deduce combinatorial criteria for the type of a real structure of a phase tropical surface.
Phase tropical surfaces can appear as a limit of a 1-parameter family of smooth complex algebraic surfaces. A phase tropical surface admits a stratified fibration over a smooth tropical surface. We study the real structures compatible with this fibration and give a description in terms of tropical cohomology. As an application, we deduce combinatorial criteria for the type of a real structure of a phase tropical surface.
Physics of internal microstructure fluid flows plays important role both due to their applications as well as their more general research field. In most occasions this type of fluid flow problems are treated with discrete models that are both computational costly as well as unable to shed light into the more general physics of the problem. In this sense a continuous model in the Eulerian frame is adopted here that consists a generalization of the incompressible Navier-Stokes equation. The present model introduces an extra tensor in the governing equations that accounts for the angular velocity of the internal microstructure, namely the micropolar model.
In 1962 Ehrhart proved that the number of lattice points in integer dilates of a lattice polytope is given by a polynomial — the Ehrhart polynomial of the polytope. Since then Ehrhart theory has developed into a very active area of research at the intersection of combinatorics, geometry and algebra.
The Ehrhart polynomial encodes important information about the polytope such as its volume and the dimension. An important tool to study Ehrhart polynomials is the h*-polynomial, a linear transform of the Ehrhart polynomial which is given by the numerator of the generating series. By a famous theorem of Stanley the coefficients of the h*-polynomial are always nonnegative integers. In this talk, we discuss generalizations of this result to weighted lattice point enumeration in rational polytopes where the weight function is given by a polynomial. In particular, we show that Stanley’s Nonnegativity Theorem continues to hold if the weight is a sum of products of linear forms that a nonnegative over the polytope. This is joint work with Esme Bajo, Robert Davis, Jesús De Loera, Alexey Garber, Sofía Garzón Mora and Josephine Yu.
In 1962 Ehrhart proved that the number of lattice points in integer dilates of a lattice polytope is given by a polynomial — the Ehrhart polynomial of the polytope. Since then Ehrhart theory has developed into a very active area of research at the intersection of combinatorics, geometry and algebra.
The Ehrhart polynomial encodes important information about the polytope such as its volume and the dimension. An important tool to study Ehrhart polynomials is the h*-polynomial, a linear transform of the Ehrhart polynomial which is given by the numerator of the generating series. By a famous theorem of Stanley the coefficients of the h*-polynomial are always nonnegative integers. In this talk, we discuss generalizations of this result to weighted lattice point enumeration in rational polytopes where the weight function is given by a polynomial. In particular, we show that Stanley’s Nonnegativity Theorem continues to hold if the weight is a sum of products of linear forms that a nonnegative over the polytope. This is joint work with Esme Bajo, Robert Davis, Jesús De Loera, Alexey Garber, Sofía Garzón Mora and Josephine Yu.
Positroids are a class of matroids that were introduced by Postnikov in 2006 that index a certain stratification of the totally non-negative Grassmannian. These matroids are famously in bijection with a “zoo” of combinatorial objects including Grassmann necklaces and plabic graphs. We introduce a new family of positroids called rook matroids that arise from restricted rook placements on a skew shaped board and discuss it in terms of this zoo. We highlight the transversal structure of rook matroids and the slightly mysterious relationship they share with lattice path matroids. This is joint work with Per Alexandersson and ongoing work with Irem Portakal and Akiyoshi Tsuchiya.
In this talk we define a new category of matroids, by working on matroid polytopes and rank preserving weak maps. This lets us introduce the concept of categorical valuativity for functors, which can be seen as a categorification of the ordinary valuativity for matroid invariants.
We also show that this new theory agrees with what we know about valuative polynomials: several known valuative polynomials can be seen as a Hilbert series of some graded vector space and we prove that these graded vector spaces let us define a valuative functor in the new sense.
Lastly, we sketch how to categorify a Theorem by Ardila and Sanchez, which states that the convolution of two valuative invariants (respectively, valuative functors) is again valuative.
This is based on a joint ongoing project with Ben Elias, Dane Miyata and Nicholas Proudfoot.
In this talk we define a new category of matroids, by working on matroid polytopes and rank preserving weak maps. This lets us introduce the concept of categorical valuativity for functors, which can be seen as a categorification of the ordinary valuativity for matroid invariants.
We also show that this new theory agrees with what we know about valuative polynomials: several known valuative polynomials can be seen as a Hilbert series of some graded vector space and we prove that these graded vector spaces let us define a valuative functor in the new sense.
Lastly, we sketch how to categorify a Theorem by Ardila and Sanchez, which states that the convolution of two valuative invariants (respectively, valuative functors) is again valuative.
This is based on a joint ongoing project with Ben Elias, Dane Miyata and Nicholas Proudfoot.
In this talk we define a new category of matroids, by working on matroid polytopes and rank preserving weak maps. This lets us introduce the concept of categorical valuativity for functors, which can be seen as a categorification of the ordinary valuativity for matroid invariants.
We also show that this new theory agrees with what we know about valuative polynomials: several known valuative polynomials can be seen as a Hilbert series of some graded vector space and we prove that these graded vector spaces let us define a valuative functor in the new sense.
Lastly, we sketch how to categorify a Theorem by Ardila and Sanchez, which states that the convolution of two valuative invariants (respectively, valuative functors) is again valuative.
This is based on a joint ongoing project with Ben Elias, Dane Miyata and Nicholas Proudfoot.
How sickled cells remember: Genetics as embodied history in Tanzania.
Thomas Mohnike (University of Strasbourg) will lecture about the transnational geographies of a Norwegian national poet between 1890 and 1918.
C*-algebra seminar by Ali Miller (Southern University of Denmark)
Speaker: Camilla Aukrust, Institute of Health and Society, UiO
The Norwegian National Opera & Ballet, the Department of Musicology and the Center for Gender Research at the University of Oslo invite you to an interdisciplinary half-day seminar related to the triple bill Bluebeard's Castle, staged by Tobias Kratzer and conducted by Edward Gardner.
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An interdisciplinary half-day seminar related to the triple bill Bluebeard's Castle, staged by Tobias Kratzer and conducted by Edward Gardner premiering at The Norwegian National Opera & Ballet, January 20.
Unni Fuskeland, Cosmology and Extragalactic Astronomy research group, Institute of Theoretical Astrophysics, University of Oslo.
How do the political determinants of health shape health outcomes in the Covid recovery era? This workshop aims to take stock of 10 years of scholarship on the political determinants of health and reflect on the future of this research agenda.
In this final seminar, Kari-Elisabeth Vambeseth Skogen will present the draft of her PhD thesis titled "The use of research in policy: A study of how civil servants engage with research knowledge".
Senter for tverrfaglig kj?nnsforskning inviterer kolleger og venner til v?rt ?rlige nytt?rsselskap. Det blir nytt?rsforedrag ved forfatter Anna Blix, mat og drikke, og utdeling av pris for beste masteroppgave med kj?nnsperspektiv.
Guest Speakers: Dr Edwin Ameso, Leipzig University and Dr Lena Kroeker, University of Bayreuth
Join us for this memorial lecture by Frank Trentmann and a discussion on sustainable consumption.