The most obvious symbols for the collections of beliefs and patterns of behavior are B and P respectively. We now can simply refer to a religion as R = <B, P> although in many cases it may be sufficient to only study B.
One argument with the definition used is that a person would hold multiple religions. In a way this is true, however it makes no sense to consider all of the subsets of B and P when discussing an individual. To make things easier, we can simply restrict B and P.
The religion held by a given individual would be the largest collection B* of beliefs and the largest collection of practices P* held by that individual and can be designated Rp = <B*, P*>
Classification and Types
However, how do you define a specific religion or group of religions in the usual sense? What collections constitute Christianity, Judaism, Hinduism, etc?
For that, we can calculate a set of summary statistics and formulate cutoff points between groups of religions and individual religions. While personal religions will vary from individual to individual, we can discuss a religion in terms of its statistical “type”: a cluster of related attributes, similar to the method of describing types of archaeological artifacts discussed by the anthropologist David Clarke.
Note that we utilized this method specifically for the definition of religion, but this can be extended to culture in general. It may be preferable however to utilize multiple instances of specializations for various cultural elements.