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Erdős Problem #1043

DISPROVED LEANdatabase updated 2025-12-28

The statement as posed is false. A solution has also been checked by machine, in Lean.

What the community database records, not our verdict. erdosproblems.com no longer shows statuses (why).

The set \(\{ z \in \mathbb{C} : \lvert f(z)\rvert\leq 1\}\)

**Erdős Problem 1043**: Let \(f\in \mathbb{C}[x]\) be a monic polynomial. Must there exist a straight line \(\ell\) such that the projection of \[\{ z: \lvert f(z)\rvert\leq 1\}\] onto \(\ell\) has measure at most \(2\)? Pommerenke [Po61] proved that the answer is no. The projection onto the line \(\ell = \mathbb{R} u\) is measured with the Lebesgue measure of that line, so `volume` of the projected set is its length. This was formalized in Lean by Alexeev using Aristotle.
Statement as formalized in Formal Conjectures (Google DeepMind, Apache-2.0) · their label: research solved · 1 further variant / known partial result in the Lean file. The authoritative wording is on erdosproblems.com/1043.
Prizenone
Topicsanalysis
Statement in LeanFormal Conjectures
Solution in Leanyes
Original pageerdosproblems.com/1043
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