Question: Skew-commuting variables in a polynomial ring

Hi,

Anyone knows how to define a ring of polynomials with variables x_1,...,x_n such that x_i*x_j = -x_j*x_i if i \neq j?

I tried using the Physics package and AntiCommutator but the problem is that in that case the variables anticommute with themselves so I have x_i^2=0.

If there is no direct way to this, I guess I could define a procedure that would look at the monomials of a polynomial and order them in lexicographic order and each time it switches two variables with different index it would multiply the monomial by -1.

I also don't know how to do that since I don't know how to look at a specific term in a monomial. For example, if my monomial is x_ix_jx_k, is there a way to find the first two variables and then switch them if LexOrder(variable1,variable2)= LexOrder(x_i,x_j)= false, i.e. if i>j?

Thanks,

M-A