Следващото заседание на семинара ще се проведе на 9 февруари 2018 г. (петък) от 13:00 часа в зала 578 на ИМИ – БАН.
Доклад на тема
ZARISKI – VAN KAMPEN TYPE THEOREMS AND CONJECTURES
ще изнесе
Петър ПЕТРОВ (MCCT, Universidade Federal Fluminense, Volta Redonda, Brazil).
Поканват се всички желаещи.
От секция „Алгебра и логика” на ИМИ – БАН
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Резюме:
The classical Zariski-Van Kampen theorem gives a presentation of the fundamental group of the complement of a complex algebraic curve in P2. A generalization of this theorem for possibly singular quasi-projective varieties was proposed by C. Eyral. As will be discussed in this talk, in both cases the relations are generated by the standard monodromy variation operators associated with the special sections of a generic pencil of hyperplanes. Next is proposed a new generalization covering a larger class of singularities than previously known. The proof uses relative monodromy variation operators, introduced by D. Chéniot and C. Eyral, which permits to unify the Zariski-Van Kampen theorem for the fundamental group and for higher homotopy groups. In the special case of non-singular varieties, the main result gives partial answer to a conjecture of D. Chéniot – C. Eyral.