I have worked with the Schur function using the following command for example
sage: Sym = SymmetricFunctions(QQ)
sage: P = Sym.p() # to expand symmetric functions in power symmetric basis
sage: s = Sym.schur()
sage: P(s([2,2]))
1/12*p[1, 1, 1, 1] + 1/4*p[2, 2] + (-1/3)*p[3, 1]
Recently I need to work with the skew Schur function. I want to expand the shifted schur function sλ(x1+y,x2+y,…,xn+y) I am guessing that it can be the following identity sλ(x1+y,x2+y,…,xn+y)=∑μsλ∖mu(y)sμ(x1,x2,…,xn) For y=1 my idenity can be proven as I am sure there is an expression. The expression sλ∖mu(y) is skew Schur function. I am wondering if there are packages in sagemath where I can work with skew schur function and verify my identity is correct or not.