Learn the גמרא דף יז: “ומלערב” (two dots) until the end of the Perek
Topic: עירוב תחומים
Is there a limit of תחום from the Torah or just drabanan?
Learn ח’ מאירי who presents the difference opinions
https://hebrewbooks.org/pdfpager.aspx?req=36399&st=&pgnum=31
https://hebrewbooks.org/pdfpager.aspx?req=36399&st=&pgnum=31
Learn ריף and רבינו יהונתן
https://hebrewbooks.org/pdfpager.aspx?req=14312&st=&pgnum=334