NUMBER THEORY
November 10, 2021 3:00 pmA phenomenon underlying many remarkable results in number theory is the natural Galois action on the cohomology of symplectic groups of integers. In joint work with Soren Galatius and Akshay...
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DIFFERENTIAL GEOMETRY
November 10, 2021 3:00 amwill speak on: Higher rank DT theory from rank 1 Fix a Calabi-Yau 3-fold X. Its DT invariants count stable bundles and sheaves on X. The generalised DT invariants of...
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CMSA EVENTS
November 10, 2021 10:00 am*Note special time* It is widely asserted that there is no such thing as a Majorana fermion in four Euclidean dimensions. This is a pity because we might like to...
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CMSA EVENTS
November 9, 2021 9:30 amOne can view a partial flag variety in C^n as an adjoint orbit inside the Lie algebra of n x n skew-Hermitian matrices. We use the orbit context to study...
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MATHEMATICAL PICTURE LANGUAGE
November 9, 2021 9:30 amQuantum maps are a popular model in physics: symplectic relations on tori are quantized to produce families of $N\times N$ matrices and the high energy limit corresponds to the large $N$ limit. They share a...
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HARVARD-MIT ALGEBRAIC GEOMETRY
November 9, 2021 3:00 pmThe classical Torelli theorem states that the Torelli map, sending a curve to its Jacobian, is an injection on points. However, the Torelli map is not injective on tangent spaces...
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CMSA EVENTS
November 9, 2021 10:30 amLocalization by cosection, first introduced by Kiem-Li in 2010, is one of the fundamental techniques used to study invariants in complex enumerative geometry. Donaldson-Thomas (DT) invariants counting sheaves on Calabi-Yau...
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CMSA EVENTS
November 4, 2021 9:00 amToday’s smartphones have enabled numerous stunning visual effects from denoising to beautification, and we can share high-quality JPEG images easily on the internet, but it is still valuable for photographers...
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ALGEBRAIC DYNAMICS
November 4, 2021 4:00 pmI will speak about recent joint work with Bell, Diller, and Jonsson in which we refute a conjecture of Bellon-Viallet by constructing (mostly) explicit examples of birational maps of projective...
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CMSA EVENTS
November 4, 2021 10:30 amTopological defects provide a modern perspective on symmetries in quantum field theory. They generalize the familiar invertible symmetries described by groups to non-invertible symmetries described by fusion categories. Such generalized...
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