talmud gemara - Who is the author of the notes Bechor Shor on Kidushin?

At the back of the gomoro Kidushin, in the Yalkut Meforshim [in the Oz Vahadar Gemoros, it seems that they were printed previously in a sefer and not at the back of the Gemoros], there are some notes from the "Bechor Shor." There are numerous different seforim printed by different people under the name of Bechor Shor. Who is the author of those notes?

Answer

The author of בכור שור is Rabbi Alexander Sender Schor (1673-1737), author of Simlah Chadasha.

He wrote בכור שור on many masechtos of Shas, including Kiddushin. All of בכור שור may be found in this sefer; the commentary to Kiddushin starts on page 444.

I checked the first comment on דף ב, and it seems to match the commentary quoted in the ילקוט מפרשים (in the Oz VeHadar edition of קידושין).