(Mishnah): If a wide roof is next to a narrow roof, the wide roof is permitted, and the narrow roof is forbidden. (We discuss when they were not Me'arev together.)

If a wide Chatzer was breached to a narrow Chatzer, the wide Chatzer is permitted, and the narrow Chatzer is forbidden, for it is like an opening of the wide one [but not vice-versa].

(Gemara): Our Mishnah discusses the same [owner's adjacent] roof, but another's roof, [even the wide roof] is forbidden. This is when it is not even, but if it is even, it is permitted.

[It discusses when his other roof] is not equal [in width], but if it is equal, [both roofs are] permitted. (We explained this like OHR SOMAYACH, Hilchos Eruvin 3:24.)