Welcome to the *Algebra and its Applications* seminar
home page!

The seminar is organized by Ettore Aldrovandi. Please send an email to contact me.

The meeting time and place is the standard one: Thursdays, at 2:00 p.m. in 104 LOV

Aug. 31 | Organizational Meeting | |
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Sept. 7 | Behrang Noohi (FSU) | Introduction to Topological Stacks I |

Sept 14 | Introduction to Topological Stacks II | |

Sept 21 | Introduction to Topological Stacks III | |

Sept 28 | Special Q&A meeting I | |

Oct 5 | Special Q&A meeting II | |

Oct 12 | Behrang Noohi (FSU) | Introduction to Topological Stacks IV |

Oct 19 | Behrang Noohi (FSU) | Fundamental groups of
topological stacks (Introduction to Topological Stacks V) |

Nov 2 | Behrang Noohi (FSU) | Algebraic topology of
topological stacks (Introduction to Topological Stacks VI) |

Nov 9 | Giles Levy (FSU) | Transformations of recurrence equations |

Nov 16 | Giles Levy (FSU) | Transformations of recurrence equations, II |

Nov 23 | Thanksgiving | |

Nov 30 | Ruben De Beerst (FSU) | Finding Bessel solutions of differential equations using generalized exponents |

Dec 5, 1:00 pm, 200 LOV Note special time, date, and place |
Emin Tatar (FSU) | (Introduction to) Differential Graded Categories |

Dec 7 | Emin Tatar (FSU) | (Introduction to) Differential Graded Categories, II |

In this expository talk we define topological stacks and
explain briefly how classical homotopy theory can be
extended to the setting of topological stacks. We
motivate this by showing that each of the following
classes of objects gives rise naturally to a class of
topological stacks: 1) graphs of groups, or more
generally, complexes of groups, 2) orbifolds, 3)
algebraic stacks over **C**, 4) topological spaces
with a group action, 5) differential groupoids, 6)
foliated manifolds. In particular, we show how certain
general results about topological stacks specialize to
certain, well-known or new, results in each of these
theories.

In order to gain more information from certain irreducible recurrence equations, an algorithm that expresses these as functions of better understood recurrence equations will be presented.

In this talk we will consider the differential equation
*x ^{2} y''(x) + x y'(x) - (x^{2} +
v^{2}) y(x) = 0* which solutions are the
modified Bessel functions. After applying the operations
"change of variables" (map

In this talk we define differential graded categories (dg-categories) and their derived categories, and show that the latter have triangulated and algebraic category structures. We also talk briefly about how derived categories are used to explain the algebraic triangulated categories.