Webification of symmetry classes of plane partitions
Ashleigh Adams, Jessica Striker
TL;DR
This work develops a lattice-word framework for the $U_q(\mathfrak{sl}_4)$-webs associated with plane partitions, focusing on symmetry classes (SPP, CSPP, TSPP, TSSCPP) and their fundamental domains. By analyzing boundary words, trips, and oscillating tableaux, the authors describe explicit lattice-word descriptions for each symmetry class and count the distinct classes. They then introduce an algorithm that projects $U_q(\mathfrak{sl}_4)$-invariants to $U_q(\mathfrak{sl}_r)$-invariants for $r=2$ or $3$ depending on the symmetry class, yielding decorated non-crossing matchings (for $r=2$) or non-elliptic $U_q(\mathfrak{sl}_3)$-webs (for $r=3$). The paper provides concrete examples mapping plane-partition–web correspondences through the projection, and sets up a framework linking benzene moves, boundary data, and promotion-like dynamics on tableaux. This connects symmetry-restricted plane partitions with representation-theoretic projections, offering a combinatorial bridge between high-rank invariants and lower-rank counterparts with potential dynamical interpretation via promotion.
Abstract
Webs are graphical objects that give a tangible, combinatorial way to compute and classify tensor invariants. Recently, [Gaetz, Pechenik, Pfannerer, Striker, Swanson 2023+] found a rotation-invariant web basis for $\mathrm{SL}_4$, as well as its quantum deformation $U_q(\mathfrak{sl}_4)$, and a bijection between move equivalence classes of $U_q(\mathfrak{sl}_4)$-webs and fluctuating tableaux such that web rotation corresponds to tableau promotion. They also found a bijection between the set of plane partitions in an $a\times b\times c$ box and a benzene move equivalence class of $U_q(\mathfrak{sl}_4)$-webs by determining the corresponding oscillating tableau. In this paper, we similarly find the oscillating tableaux corresponding to plane partitions in certain symmetry classes. We furthermore show that there is a projection from $U_q(\mathfrak{sl}_4)$ invariants to $U_q(\mathfrak{sl}_r)$ for $r=2,3$ for webs arising from certain symmetry classes.
