* Seuraavan viikon tapahtumat merkitty tähdellä
Madeline Nurcombe (The University of Sydney)
The ghost algebra and the dilute ghost algebra
* Today * Thursday 26 February 2026, 09:00, U250a
The Temperley-Lieb (TL) algebra has a wide range of applications, from physical models of polymers and quantum spin chains, to knot theory. Its basis elements can be expressed as rectangular diagrams of non-crossing strings, with multiplication based on concatenation of diagrams. There are also one- and two-boundary TL algebras, describing physical systems with boundaries, but the two-boundary TL algebra requires its diagrams to have an even number of strings connected to each boundary. In this talk, I will introduce the ghost algebra, a two-boundary generalisation of the TL algebra that allows diagrams with odd or even numbers of strings at each boundary. Its diagrams contain ghosts: dots on the boundaries that act as bookkeeping devices to ensure associativity of multiplication. I will also introduce the dilute generalisation of the ghost algebra, and discuss the lattice models associated with these algebras.
Mathematical physics seminar
Johanna Immonen (Aalto)
Midterm presentation
* Friday 27 February 2026, 11:00, M2 (M233)
Nataliia Kushnerchuk
What is a graphical model?
* Monday 02 March 2026, 14:15, Y313
This is an overview presentation about graphical models. We'll explore the definitions and key properties of graphical models. We'll discuss them from the perspective of algebra, geometry, and combinatorics through several examples. Everyone is welcome!
AGC Seminar
Boris Kjær (University of Copenhagen)
A rigorous approach to topological order in the thermodynamic limit (Remote talk)
* Tuesday 03 March 2026, 11:00, M3 (M234)
In recent years, the analysis of topologically ordered ground states of 2d quantum lattice systems in the thermodynamic limit has been developed to provide a rigorous invariant of gapped phases. The methodology is based on the approach of Doplicher, Haag, and Roberts in the context of algebraic quantum field theory, and derives a braided C*-tensor category representing the anyonic excitations of the ground state, and the fusion and braiding among them. We present the computation of this category for a complete class of commuting projector Hamiltonians, the Levin-Wen models.
Theo Elenius
Midterm review
* Wednesday 04 March 2026, 10:15, M3 (M234)
Seminar on analysis and geometry
Dr. Kirsten Morris (Virginia Tech)
Graphical Analysis of Dyadic and Quasi-Dyadic Codes
Thursday 05 March 2026, 15:15, M2 (M233)
Dyadic matrices are a class of matrices known as reproducible matrices, where the entries of the matrix are completely determined by their first row. Quasi-dyadic matrices are arrays with dyadic matrices in the blocks. In this work, we explore classical and quantum CSS code constructions arising from dyadic and quasi-dyadic matrices. We explore the properties that their resulting Tanner graphs have, including girth, cycle structures, and absorbing sets. We establish construction conditions to avoid small cycles, as these can be detrimental for decoding. This is joint work with Anthony Gómez Fonseca, Gretchen Matthews, and Tefjol Pllaha.
GyeongHyeon Nam (Aalto)
TBA
Monday 09 March 2026, 14:15, M134
TBA
AGC Seminar
Eetu Reijonen
On the effect of socioeconomic conditions on population health --- Prediction of disease burden in OECD countries (MSc thesis presentation)
Monday 09 March 2026, 15:15, Y405
Dr. John Urschel (MIT)
TBA
Tuesday 10 March 2026, 15:15, U5 (U147)
Riku Anttila (University of Jyväskylä)
Uniqueness of sign-changing solutions to Trudinger's equation
Wednesday 11 March 2026, 10:15, M3 (M234)
We establish uniqueness for sign-changing solutions to Trudingers parabolic equation with time dependent $C^2$ Dirichlet boundary data.
This talk is based on my joint work with Peter Lindqvist and Mikko Parviainen; preprint available at arXiv:2602.04748.
Seminar on analysis and geometry
Sylvester Eriksson-Bique (University of Jyväskylä)
p-Dirichlet structures, the resistance conjecture and energy image density property
Wednesday 11 March 2026, 11:15, M3 (M234)
We develop the axioms for p-dirichlet structures. This abstract framework unifies different approaches and leads to new results in conformal geometry. We show how two conjectures that were open for Dirichlet spaces can be shown to hold in this very general setting. In fact, the proofs came from thinking in this general framework. The talk includes joint work with Riku Anttila, Mathav Murugan and Lassi Rainio.
Seminar on analysis and geometry
Matematiikan kandiseminaari (Bachelor thesis seminar in Math.)
Thursday 12 March 2026, 09:00, TBA
Further information
Ohjelma: https://mycourses.aalto.fi/course/view.php?id=34597#module-908887
Lilja Metsälampi (Aalto)
TBA
Monday 23 March 2026, 14:15, M134
TBA
AGC Seminar
Petteri Kaski (Aalto)
Algebraic complexity of tensors with three or more modes
Monday 30 March 2026, 14:15, M134
The algebraic complexity of bilinear maps and trilinear forms has been studied extensively, most notably in the context of complexity of matrix multiplication; for three-mode tensors, it is known that asymptotic circuit complexity and asymptotic rank coincide, but for tensors with more than three modes this asymptotic correspondence in general breaks down. This talk develops the basic correspondence for three modes as well as looks at recent work towards understanding the complexity of tensors with more than three modes. Based in part on joint work with Cornelius Brand, Radu Curticapean, Baitian Li, Ian Orzel, Tim Seppelt, and Jiaheng Wang (cf. https://arxiv.org/abs/2602.11975 ).
AGC Seminar
Jaakko Olkkonen (Aalto)
TBA (Mid-term review)
Wednesday 01 April 2026, 10:00, M3 (M234)
Numerical Analysis seminar
Philémon Bordereau (EPFL)
TBA
Tuesday 07 April 2026, 10:15, M3 (M234)
MSc Ian Välimaa (Aalto)
TBA (Mid-term review)
Monday 20 April 2026, 14:15, M3 (M234)
Aalto Stochastics & Statistics Seminar / Leskelä
Akseli Jussinmäki
TBA (Mid-term review)
Wednesday 22 April 2026, 10:15, M3 (M234)
Seminar on analysis and geometry
Matematiikan kandiseminaari (Bachelor thesis seminar in Math.)
Friday 08 May 2026, 09:00, TBA
Further information
Ohjelma: https://mycourses.aalto.fi/course/view.php?id=34597#module-908887
Zofia Grochulska
TBA
Wednesday 13 May 2026, 10:15, M3 (M234)
Seminar on analysis and geometry / Korte
Matematiikan kandiseminaari (Bachelor thesis seminar in Math.)
Monday 15 June 2026, 09:00, TBA
Further information
Ohjelma: https://mycourses.aalto.fi/course/view.php?id=34597#module-908887
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