 For example, the binomial formula
which is valid for any two elements "a" and "b" in any commutative ring "R" is understood in this sense by interpreting the binomial coefficients as elements of "R" using this map.Given two "R"-algebras "S" and "T", their tensor product
is again a commutative "R"-algebra.In some cases, the tensor product can serve to find a "T"-algebra which relates to "Z" as "S" relates to "R".