Intervals of balanced binary trees in the Tamari lattice

  • Authors:
  • Samuele Giraudo

  • Affiliations:
  • -

  • Venue:
  • Theoretical Computer Science
  • Year:
  • 2012

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Abstract

We show that the set of balanced binary trees is closed by interval in the Tamari lattice. We establish that the intervals [T,T^'], where T and T^' are balanced binary trees are isomorphic as posets to a hypercube. We introduce synchronous grammars that allow to generate tree-like structures and obtain fixed-point functional equations to enumerate these. We also introduce imbalance tree patterns and show that they can be used to describe some sets of balanced binary trees that play a particular role in the Tamari lattice. Finally, we investigate other families of binary trees that are also closed by interval in the Tamari lattice.