Laws of Idolatry. When the Torah says "this and that" there is an argument between R Yoshiyahu and R Yonathan whether it means this or that or both, or if it means it has to be both. This comes up in Bava Metzia chapter 11.
This might explain the the fact that the Rambam says a city that has been seduced to serve idolatry "ir hanadachat" is from 100 to the majority of a tribe but also that the number of people that have been seduced can not be less than 100. However anywhere from 200 and up, it is enough to have the majority of the city. So it looks like the Rambam is understanding you need two conditions in order to be a ir hanidachat. It has to be a city of no less than hundred and that you need no less that 100.
This way of looking at that Gemara does require some explanation. The way Tosphot understands it along with most other rishonim is the city has to be no less than 100 but the actual number of seduced people is just the majority; i.e. 51 in a city of 100. Why in a city of 100 you need the whole city is hard to understand unless the Rambam is understanding that you need the city itself and the number of those seduced to be two condition that you need both like the opinion when the Torah says this and that it means both together.
[You can see why I stay away from the religious world as far as possible since I think they all are deeply into idolatry except for the people that follow the Gra. You can see that the Torah takes a dim view of worship of any being besides God alone.]
