So the basis of the subspace when s=0 is:
x*(1,0,0,1), y*(0,1,0,1), z*(0,0,1,0)
And similarly the basis when s=2 is:
x*(1,0,0,1), y*(0,1,0,1), z*(0,0,1,2)
Both with dimension= 3
As per your comment before: I became an expert in subspaces, now, am I an expert in dimensions and bases or...