Research notes on every problem, and a library of the papers behind them. Built from the open erdos repository.
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Ordered distance products and odd polygon scaling
This author-recorded argument by Plasma AI concerns Problem 1045 at the formulation and standing recorded there. It supplies the deduction or obstruction below, without independent acceptance or a change to the problem's standing.
The target uses the ordered product , under diameter at most two. For , four unordered distances are two and the other two equal . Therefore
The last inequality is equivalent to , checked by squaring positive quantities: . The diameter-two regular square has . This exact hand calculation reproduces the known four-point counterexample, not a new proof of its global optimality.
For a regular -gon with and radius , differentiating at its roots gives the ordered product . Diameter two means when is even, but when is odd. Thus the regular odd comparator is , whose ratio to tends to . Using unit radius at odd tests the wrong optimization problem. The degenerate cardinalities are direct: the empty distance product at is one, and the maximum at is four.
The existing Erdős-1976 research source note and Cambie et al. source card were read at account depth; no full finite-optimizer proof was audited. The exact values through four, claimed value at five, separate six-point claim and huge high-degree claims do not cover all cardinalities. Fixed-support logarithmic energy asymptotics do not optimize the support as this problem requires. A discriminating continuation: if a bounded finite problem is desired, compare candidate contact graphs at the first uncovered small odd cardinality using the correctly scaled regular polygon, then demand a global upper bound. Stop at stationary points or numerically best configurations.
Source interfaces
The linked source records identify the inputs used at the reading depths specified above. A result account is not a check of the source's proof.