We have already looked at groups and on these pages we look at other algebraic structures.
For a more greneral discussion of algebras see the page here.
FAlgebras
An algebra consists of:

If the datatype is denoted 'A' then going one layer up in this tree structure can be denoted: F(A).
So to evaluate an expression we need a function α: F(A) > A
More about falgebra here.