A word has a shape determined by its image under the Robinson-Schensted-Knuth correspondence. We show that when a word \(w\) contains a separable (i.e., \(3142\)- and \(2413\)-avoiding) permutation \(\sigma\) as a pattern, the shape of \(w\) contains the shape of \(\sigma\). As an application, we exhibit lower bounds for the lengths of supersequences of sets containing separable permutations.
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