Rav in Miami and author of responsa
Rabbi Shmuel Tuvia Stern and the Miami Eruv Discussion With the Rebbe
Rabbi Shmuel Tuvia Stern is the Rav named in Rabbi Shmuel Zajac's account of the Miami exchange at the Yud Shevat 5743 farbrengen.
The exchange about Miami
Rabbi Shmuel Zajac relates that Rabbi Stern told the Rebbe he had made an eruv in Miami. The Rebbe's immediate question was whether Miami had shishim ribo—six hundred thousand people.
The response goes to the status of the city itself. Before considering the details of poles and wires, the halachic character of the streets and the scale of public movement had to be addressed.
Why the question matters
Shishim ribo is a major part of the dispute over reshus harabim. Some poskim require six hundred thousand people to pass along a particular street; others look to the city or its public system more broadly, and some do not require that condition at all.
The Rebbe's question, as Rabbi Zajac reports it, shows that a large-city eruv could not be discussed without confronting this issue. It was not enough to point to a constructed boundary.
The Yud Shevat farbrengen
The complete Yud Shevat 5743 farbrengen survives in six audio tracks. The brief exchange has not been isolated to a reliable timestamp, so the account is given in Rabbi Zajac's name rather than placed in quotation marks as a transcript.
Rabbi Stern's role is important because the episode concerns a Rav who had actually established a city eruv and raised it directly with the Rebbe.