ABSTRACT
Usually, Yakov Borisovich telephoned me at seven in the morning. ‘Doesn’t it seem to you…’ he would say, and there would then follow some sort of paradox. The last such call was two weeks before his death. He talked about the strange, ‘chaotic’ behaviour of solutions for the Riccati equations with periodic coefficients.117 This work (together with a coauthor whose name I have forgotten) remained unwritten, and I will write about it here in a little detail.
