论文信息 - Compact subsemigroups of (βℕ, +) containing the idempotents

Compact subsemigroups of (βℕ, +) containing the idempotents

The space βℕ is the Stone-Cech compactification of the discrete space of positive integers. The set of elements of βℕ which are in the kernel of every continuous homomorpnism from βℕ to a topological group is a compact semigroup containing the idempotents. At first glance it would seem a good candidate for the smallest such semigroup. We produce an infinite nested sequence of smaller such semigroups all defined naturally in terms of addition on ℕ.

Neil Hindman | Dona Strauss | D. Strauss | N. Hindman

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