Abstract: 

Ancient solutions of Ricci flow appear naturally in the singularity analysis.

For type I solutions all such singularity models are shrinking Ricci solitons and we have examples of singularity models which are steady Ricci solitons. We also have many examples of ancient solutions which are not singularity models and are not Ricci solitons.  In this talk we survey some known examples of ancient solutions of Ricci flow which are not Ricci solitons.