Elishama shmuel Gutfreund asks:
8 lines down on pesachim daf zayin 7. it says bitul in your heart how does that work according to tosfos? (which mefarish brings the answer?)
Elishama shmuel Gutfreund, United States waterbury
The Kollel replies:
The Ran at the beginning of the Masechta, 1a in Rif pages DH uMahu, brings our Gemara and writes that bitul works because it is hefker. Even though hefker in one's heart does not usually work, with chometz it is different, because chometz is not really in a person's possession but the Torah made it like it is in his possession (see Gemara end 6b). Therefore a "Giluy Daata" is sufficient to take the chometz out of his reshus and a person can have this intention merely in his heart.
Shabbat Shalom
Dovid Bloom