Gal Amram: Hagendorf’s problem

Shalom

We hold seminar on Tuesday , June 12,

time 16:00-17:30, seminar room: 201.

Speaker: Gal Amram(BGU)

Title: Hagendorf’s problem

Abstract: If a linear order L, has the order type of an ordinal, then L satisfies the following property;

If L'<L, then L’+1<=L. In 1977 J.Hagendorf asked, if  L is an order type that is strictly right indecomposable and posses this property, is L necesarily an indecomposanle ordinal ?

In 1978 J.Larson proved that this is the case when L is assumed to be scattered. The talk will deal with the posibility of the existence of a $\sigma$-scattered order type, which satisfies  the properties in Hagendorf’s question, but it is not well ordered.