On hopfian groups

نویسندگان

چکیده

برای دانلود رایگان متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

منابع مشابه

On co-Hopfian nilpotent groups

We characterize co-Hopfian finitely generated torsion free nilpotent groups in terms of their Lie algebra automorphisms, and construct many examples of such groups.

متن کامل

Braid Groups Are Almost Co-hopfian

We prove that the braid group on 4 or more strands modulo its center is co-Hopfian. We then show that any injective endomorphism of these braid groups is geometric in the sense that it is induced by a homeomorphism of a punctured disk. We further prove that any injection from the braid group on n strands to the braid group on n + 1 strands is geometric (n ≥ 7). Additionally, we obtain related r...

متن کامل

Braid Groups and the Co-hopfian Property

Let B n be the braid group on n 4 strands. We prove that B n modulo its center is co-Hoppan. We then show that any injective endomorphism of B n is geometric in the sense that it is induced by a homeomorphism of a punctured disk. We further prove that any injection from B n to B n+1 is geometric for n 7. Additionally, we obtain analogous results for mapping class groups of punctured spheres. Th...

متن کامل

Hopfian and strongly hopfian manifolds

Let p : M → B be a proper surjective map defined on an (n+ 2)-manifold such that each point-preimage is a copy of a hopfian n-manifold. Then we show that p is an approximate fibration over some dense open subset O of the mod 2 continuity set C′ and C′ \O is locally finite. As an application, we show that a hopfian n-manifold N is a codimension-2 fibrator if χ(N) 6= 0 or H1(N) ∼= Z2.

متن کامل

Hopfian and co-hopfian subsemigroups and extensions

This paper investigates the preservation of hopficity and co-hopficity on passing to finite-index subsemigroups and extensions. It was already known that hopficity is not preserved on passing to finite Rees index subsemigroups, even in the finitely generated case. We give a stronger example to show that it is not preserved even in the finitely presented case. It was also known that hopficity is...

متن کامل

ذخیره در منابع من


  با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید

ژورنال

عنوان ژورنال: Pacific Journal of Mathematics

سال: 1970

ISSN: 0030-8730,0030-8730

DOI: 10.2140/pjm.1970.32.753