Computability in Europe 2008
Logic and Theory of Algorithms
|Slot:||Thu, 11:00-11:20, Room 24 (col. 3)|
The paper gives an overview over recent results of the author on various upper semilattices of many-one degrees. The local isomorphism type (i.e. the collection of isomorphism types of all principal ideals) of $m$-degrees belonging to any fixed class of arithmetical hierarchy is completely described. The description of the semilattices of simple, hypersimple and $\Delta^0_2$ $m$-degrees up to isomorphism is also given.
|websites: Arnold Beckmann||2008-05-18|