Almost all introductory texts on Schubert calculus discuss the Grassmannian case only. Does there exist a nice discussion of the full flag manifold case $SU(N)/T^{N-1}$? A low dimensional example along the lines of this excellent [answer][1] would be appreciated. 


  [1]: https://mathoverflow.net/questions/196546/hard-lefschetz-theorem-for-the-flag-manifolds