12 papers
Boundary case of equality in optimal Loewner-type inequalities
Victor Bangert, Christopher Croke, Sergei V. Ivanov +1
We prove certain optimal systolic inequalities for a closed Riemannian manifold (X,g), depending on a pair of parameters, n and b. Here n is the dimension of X, while b is its firs…
Generalized degree and optimal Loewner-type inequalities
Sergei V. Ivanov, Mikhail G. Katz
We generalize optimal inequalities of C. Loewner and M. Gromov, by proving lower bounds for the total volume in terms of the homotopy systole and the stable systole. Our main tool…
Filling area conjecture and ovalless real hyperelliptic surfaces
Victor Bangert, Christopher Croke, Sergei V. Ivanov +1
We prove the filling area conjecture in the hyperelliptic case. In particular, we establish the conjecture for all genus 1 fillings of the circle, extending P. Pu's result in genus…
On identities in groups of fractions of cancellative semigroups
S. V. Ivanov, A. M. Storozhev
To solve two problems of Bergman stated in 1981, we construct a group such that contains a free noncyclic subgroup (hence, satisfies no group identity) and , as a gr…
On varieties of groups in which all periodic groups are abelian
S. V. Ivanov, A. M. Storozhev
To solve a number of problems on varieties of groups, stated by Kleiman, Kuznetsov, Ol'shanskii, Shmel'kin in the 1970's and 1980's, we construct continuously many varieties of gro…
Non-hopfian relatively free groups
S. V. Ivanov, A. M. Storozhev
To solve problems of Gilbert Baumslag and Hanna Neumann, posed in the 1960's, we construct a nontrivial variety of groups all of whose noncyclic free groups are non-hopfian.