There are some [women] who are permitted to their husbands but forbidden to their yavam; [some who are] permitted to their yavam but forbidden to their husbands; [some who are] permit- ted to both; and [some who are] forbidden to both.  These are [the ones] permitted to their husbands but forbidden to their yavam: an ordinary Kohen who married a widow, and who has a brother [who is] Kohen Gadol; a chalal who married a qualified woman, and who has a brother [who is a] qualified [Kohen]; a Yisrael who married the daughter of a Yisrael, and who has a brother [who is] a mamzer; a mamzer who married a mamzeress, and who has a brother [who is] a Yisrael —- [these are] permitted to their husbands but forbidden to their yavam.