Key points are not available for this paper at this time.
In this paper, we give a formula for the number of permutations that avoid the split patterns 3|12 and 23|1 with respect to a position r. Such permutations count the number of Schubert varieties for which the projection map from the flag variety to a Grassmannian induces a fiber bundle structure. We also study the corresponding bivariate generating function and show how it is related to modified Bessel functions.
Grigsby et al. (Tue,) studied this question.
Synapse has enriched 5 closely related papers on similar clinical questions. Consider them for comparative context: