Ketubot 73: When Is a Marriage a Marriage?

A machloket between Rav and Shmuel on the previous mishnah: whether a conditional betrothal requires a get if the condition is not met. And the ramifications of those different approaches. Plus, several cases where it would seem clear that a get is not warranted - but that a get is required nonetheless. Possibly at a rabbinic level of requirement, which seems particularly difficult, as compared to the Torah standard that would leave her free to marry anyone.