The Kahn–Saks conjecture on balance in wide posets

From papers

Let PP be a finite poset, let w(P)w(P) denote its width, and let δ(P)\delta(P) be the maximum, over distinct x,yPx,y\in P, of minp(xy),p(yx)\min\\{p(x\prec y),p(y\prec x)\\}. The Kahn–Saks conjecture. If the width tends to infinity, then

w(P)δ(P)12.w(P)\longrightarrow\infty \quad\Longrightarrow\quad \delta(P)\longrightarrow \frac12.

The conjecture predicts asymptotically optimal balance for posets of growing width. The text identifies it as still open; it is related to several stronger-looking parameter conjectures developed later in the paper.

Progress summary

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

Sources & referencesView supporting material

Primary source

Max Aires and Jeff Kahn, “Balancing Extensions in Posets of Large Width”, arXiv:2509.11549 (2025).

Additional references

4 papers in this index state this conjecture (2018–2025). The statement above is taken from the most recent of them; the others are arXiv:2311.02743, arXiv:2005.08390, arXiv:1811.01500.

Solutions 0

No solutions have been posted yet.