The marked mesh-pattern characterization of permutations with RSK tableaux avoiding $(3,2)$

Under the Robinson–Schensted–Knuth correspondence, a permutation is mapped to a pair of Young tableaux of the same shape. Let $A$ be the set of permutations whose tableaux avoid the Young-diagram shape $(3,2)$, and let the displayed four marked mesh patterns be interpreted in the marked-mesh-pattern sense. RSK shape-avoidance conjecture. The permutations whose tableaux under the RSK map avoid the shape $(3,2)$ are precisely the avoiders of the four marked mesh patterns displayed in the source. The claim extends the corresponding hook-shape observation and proposes an explicit pattern-avoidance description for a non-hook Young-tableau shape; no resolution is stated.