Calf Seminar
About the Calf
Calf is the junior COW, an algebraic geometry seminar group primarily aimed at PhD students.
The organisers for academic year 2020/21 are Calla Tschanz (Bath), Geoffrey Mboya (Oxford) and Joe Prebble (Loughborough), and we have an extensive network of local organisers at different universities. Calf announcements are made using the COW mailing list. If you would like to get involved in the organisation, or suggest your institution as the next venue, please contact either of the people named above.
The COW seminar has some funding for travel expenses, and information on reimbursement can be found on the main COW webpage.
Due to the current situation with COVID-19, we are organising a series of online seminars via Zoom. The link to join will be in an email announcement made via the COW mailing list. If you do not have the link and wish to attend, please email one of the organisers.
About the Calf
Calf is the junior COW, an algebraic geometry seminar group primarily aimed at PhD students.
The organisers for academic year 2020/21 are Calla Tschanz (Bath), Geoffrey Mboya (Oxford) and Joe Prebble (Loughborough), and we have an extensive network of local organisers at different universities. Calf announcements are made using the COW mailing list. If you would like to get involved in the organisation, or suggest your institution as the next venue, please contact either of the people named above.
The COW seminar has some funding for travel expenses, and information on reimbursement can be found on the main COW webpage.
Due to the current situation with COVID-19, we are organising a series of online seminars via Zoom. The link to join will be in an email announcement made via the COW mailing list. If you do not have the link and wish to attend, please email one of the organisers.
Upcoming Meeting:
Online Calf Seminar, Friday 11th December 2020
15:00 Arkadij Bojko (Oxford)
Title: Computing with virtual fundamental classes of Hilbert schemes on Calabi--Yau 4-folds
Abstract: Joyce introduced a new approach to wall-crossing for \C-linear enumerative theories by constructing a vertex algebra on the homology of the stack of coherent sheaves. A conjectural application of this theory is a wall-crossing formula of virtual fundamental cycles in Calabi--Yau 4-folds which were introduced in recent years. We apply this framework to virtual fundamental classes of Hilbert schemes, by considering an insertion given by the top Chern class of a tautological vector bundle $L^{[n]}$ associated to any line bundle $L$ on $X$. We prove that the conjectural formula of Cao--Kool for these invariants holds for any $L$ if it is true for any smooth divisor. Assuming this, we also give an explicit expression of the virtual fundamental class of Hilbert schemes and 0-dimensional sheaves, which allows us to compute with other insertions.
Meetings are announced via the COW mailing list. If you would like to give a talk, please contact one of the organisers.
Recent Past Meeting:
Online Calf Seminar, Friday 20th November 2020
15:00 Tiago Guerreiro (Loughborough)
Title: On Singular Fano 3-folds complete intersections and their birational geometry
Abstract: The Minimal Model Program aims at finding good representatives in a birational equivalence class. Starting from a 3-dimensional smooth projective variety W, Mori has shown that W can be dismantled by a sequence of birational transformation to a either a Minimal Model or a Mori Fibre Space. The outcomes of the minimal model program are rarely unique although relations between minimal models are well understood in general. On the other hand, Mori Fibre Spaces relate to each other in more complicated and unexpected ways. In this talk I will aim to give a flavour of these relations and explain how this problem relates to rationality questions.
Contact one of the organisers to get the recorded talk.
Online Calf Seminar, Friday 11th December 2020
15:00 Arkadij Bojko (Oxford)
Title: Computing with virtual fundamental classes of Hilbert schemes on Calabi--Yau 4-folds
Abstract: Joyce introduced a new approach to wall-crossing for \C-linear enumerative theories by constructing a vertex algebra on the homology of the stack of coherent sheaves. A conjectural application of this theory is a wall-crossing formula of virtual fundamental cycles in Calabi--Yau 4-folds which were introduced in recent years. We apply this framework to virtual fundamental classes of Hilbert schemes, by considering an insertion given by the top Chern class of a tautological vector bundle $L^{[n]}$ associated to any line bundle $L$ on $X$. We prove that the conjectural formula of Cao--Kool for these invariants holds for any $L$ if it is true for any smooth divisor. Assuming this, we also give an explicit expression of the virtual fundamental class of Hilbert schemes and 0-dimensional sheaves, which allows us to compute with other insertions.
Meetings are announced via the COW mailing list. If you would like to give a talk, please contact one of the organisers.
Recent Past Meeting:
Online Calf Seminar, Friday 20th November 2020
15:00 Tiago Guerreiro (Loughborough)
Title: On Singular Fano 3-folds complete intersections and their birational geometry
Abstract: The Minimal Model Program aims at finding good representatives in a birational equivalence class. Starting from a 3-dimensional smooth projective variety W, Mori has shown that W can be dismantled by a sequence of birational transformation to a either a Minimal Model or a Mori Fibre Space. The outcomes of the minimal model program are rarely unique although relations between minimal models are well understood in general. On the other hand, Mori Fibre Spaces relate to each other in more complicated and unexpected ways. In this talk I will aim to give a flavour of these relations and explain how this problem relates to rationality questions.
Contact one of the organisers to get the recorded talk.
This page is maintained by Chris Seaman.
