Universal lower bound conjecture for binary search tree height of permuton samples

Let cmathcalPμncmathcal{P}^n_\mu be a sample of nn points from a permuton cmucmu, and let cmathcalTPμncmathcal{T}\langle\mathcal{P}^n_\mu\rangle be the corresponding binary search tree, with height denoted by h(TPμn)h(\mathcal{T}\langle\mathcal{P}^n_\mu\rangle). Let cc^* be the unique solution with c2c\geq 2 of

clog(2e/c)=1.c\log(2e/c)=1.

Universal height lower-bound conjecture. For any permuton cmucmu and cvarepsilon>0cvarepsilon>0,

limnP[h(TPμn)logn<cε]=0.\lim_{n\to\infty}\mathbb{P}\left[\frac{h\left(\mathcal{T}\langle\mathcal{P}^n_\mu\rangle\right)}{\log n}<c^*-\varepsilon\right]=0.

The conjecture asserts that the uniform-permuton constant cc^* is a universal lower bound for the typical logarithmic height of binary search trees built from permuton samples, even when the hypotheses of the proved universality theorem fail. The paper notes that no permuton with asymptotically smaller height and non-vanishing probability is known, while examples show that the height can be larger than clognc^*\log n.

Sources & referencesView supporting material

Primary source

Benoît Corsini, Victor Dubach and Valentin Féray, “Binary search trees of permuton samples”, arXiv:2403.03151 (2025).

Progress summary

Never refreshed

Nothing recorded yet. Refresh searches the literature and the public web for attempts on this problem, and writes the first summary here.

Solutions 0

No solutions have been posted yet.