The Different Recensions of Halakhot Gedolot
The textual situation is very complicated and has yet to be explored in the requisite depth. The only version available for several centuries was the editio princeps (Venice 1548), until a second recension was printed in the middle of the nineteenth century, on the basis of a Vatican manuscript For nearly a century, scholarly discussions of the text and recensions of Halakhot Gedolot depended exclusively on these two editions. One outstanding difference, which served as the basis for various theories, is that the Vatican text contains numerous Geonic responsa (by authors dating up to the turn of the tenth century), which clearly represent secondary interpolations. The presence or absence of these responsa was therefore taken as the litmus test for classifying versions of the text and as the foundation of attempts to reconstruct its history. A. Epstein, for example, considered the recension reflected in the editio princepts to represent R. Simeon Qayyara’s work and the Vatican manuscript to represent an augmented edition, while [Louis] Ginzberg saw the first recension as a reworking, by an anonymous disciple, or an original Halakhot Gedolot composed by Yehudai Gaon and attributed the augmented recension to R. Simeon Qayyara. Both these scholars agreed that the more original version of the work was used by the medieval rabbinic authorities in France and Germany, and the augmented recension by those in Spain, Provence, and North Africa; as a result, this recension was identified (not quite accurately) with the “Spanish Halakhot Gedolot” occasionally cited by Franco-German authors. The recent publication of E. Hildesheimer’s variorum edition represents a significant step forward, although there is still considerable room for improvement. Among the editor’s more important discoveries was the fact that the development of varying recensions preceded the interpolation of Geonic responsa; in fact, we now know that such interpolations were not restricted to one particular recension. The nature of the relationship between the basic versions of the two recensions, however, has yet to be adequately clarified.
(The Geonim of Babylonia and the Shaping of Medieval Jewish Culture, 223-4)
My teacher Neil Danzig has also written about Halakhot Gedolot and its issues, see Mavo Le-Sefer Halakhot Pesukot, 180-242. He commented that “דיון מפורט באשר לכל העדויות לס’ הלכות גדולות ויחסן זו לזו, הוא נושא מסובך שמחכה לגואלו”. (ibid., 186) After a preliminary comparison, he wrote that the recension on which the Berlin edition from the Vatican MS is based, before the Geonic responsa were added, seems to be the earliest recension that we have today. (ibid., 189) He emphasized that the subject requires much more examination. The Venice edition of 1548 can be found here and the Berlin edition here. I know that more research is being done on Halakhot Gedolot and hopefully some of the questions raised will be answered.
Eruvonline has an excellent discussion of one of the differences found between the recensions of Halakhot Gedolot, that being whether shishim ribo (600,000 people) is a requirement for a reshut ha-rabbim. (hat tip)
What the legal implications might be of differences between various recensions of halakhic works is not an easy question to answer. On the one hand, you can argue that a certain halakhic tradition may have been accepted as authoritative by certain authorities because they felt that it was reflective of the composition itself and the claim that it is not original to the composition would therefore undermine this tradition’s authority. On the other hand, you can argue that the very fact that it was accepted as authoritative is not connected to it being original to the composition. Much of this depends on whether we can even talk about authoritative recensions and editions, a subject which has discussed by numerous scholars.