The Permutation Classes Equinumerous to the Smooth Class

@article{Bna1998ThePC,
  title={The Permutation Classes Equinumerous to the Smooth Class},
  author={Mikl{\'o}s B{\'o}na},
  journal={Electr. J. Comb.},
  year={1998},
  volume={5}
}
We determine all permutation classes defined by pattern avoidance which are equinumerous to the class of permutations whose Schubert variety is smooth. We also provide a lattice path interpretation for the numbers of such permutations.