Kolloquium Wilhelm Killing: Prof. Dr. Piotr Achinger (IMPAN): Homotopy types in algebraic geometry
Thursday, 27.06.2019 16:30 im Raum M5
Abstract:
Algebraic topology studies algebraic invariants of topological spaces,
typically identifying spaces which are "homotopy equivalent." Homotopy
theory proved essential in the study of topological spaces; when
applied to algebraic varieties, its ideas turn out to be even more
powerful, as the resulting invariants have far more structure, often
coming from either complex analysis (Hodge theory) or arithmetic (an
action of a Galois group). In particular, as predicted e.g. by the
Hodge conjecture, the Tate conjecture, or Grothendieck?s section
conjecture, they should be able to detect algebraic cycles and
rational points.
Over the field of complex numbers, an algebraic variety gives rise to
a nice topological space to which one can apply methods of algebraic
topology directly. From the point of view of arithmetic and algebraic
geometry over more general fields, it is of key importance to
construct algebraically defined topological invariants. Probably the
most successful development to this date achieving this goal is the
introduction of the etale topology by Artin and Grothendieck, and the
etale homotopy type of Artin and Mazur.
I will give a gentle introduction to this circle of ideas, explain
several ways in which one can associate a homotopy type to an
algebraic variety, and discuss how the resulting objects witness
phenomena quite foreign to classical algebraic topology of nice
topological spaces.
Angelegt am 21.03.2019 von Sandra Huppert
Geändert am 24.06.2019 von Anne Schindler
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