After the section of Gemara in most sefarim, before the Rosh there is a section of the Piskei Tosfos. Who authored this work?
Per Rabbi Yaakov Emden in his Sefer Mishna Lechem Pesachim Chapter 10 it was authored by Rabbi Yaakov ben Asher - the Tur. There are those who attribute it to the Tur's father - the Rosh. The Chida in Shem HaGedolim questions as to what the source is that it was written by either the Tur or the Rosh.
There are those that say it was authored by Rabbi Chezkiya or Rabbi Yechezkia the uncle of Rabbi Eliezer Matuch. Also mentioned as a possible author is Rabbi Yaakov ben Rabbi Meir Katz from Nordhausen who was killed in 1349 due to the black death and subsequent black death Jewish persecutions.