SearcharxivSearch

arXiv subjects

Maurizio Falconi

Publications and source records attributed to Maurizio Falconi.

2 recordsLinked to original sources

Minimum central circles: an effective characterization of the global asymptotic constant

Let ${R^\ast}(n)$ be the least radius of a central circle to which nonoverlapping circles of radii $1,\ldots,n$ are externally tangent. We prove that ${R^\ast}(n)={C_\ast} n^2+o(n^2)$ and characterize ${C_\ast}$ by finite linear programs with an explicit error tending to zero. The reduction preserves arbitrary orders and all pairwise constraints: the limiting problem places marked points on a line at pairwise separation at least the geometric mean of their marks. Concatenation with a bounded boundary cost proves existence, and balanced finite-word programs supply matching effective upper and lower bounds. Their certified gap is $(1/k+1/r)/π$, before directed arithmetic error, for $k$ mark types and words of length $r$. A quantitative reflected-block recovery theorem supplies genuine permutations and full ring geometry, with a countable extension and a strict four-block improvement. The explicit interval is $C_{\mathrm{term}}+η_{\mathrm{width}}\le{C_\ast}\le U_4$; neither endpoint is asserted sharp. In particular, the coefficient $1/8$ proposed in the preceding finite study is false. An elementary expression for ${C_\ast}$, efficient high-precision evaluation and global floating-circle structure remain open.

math.MG

Arranging circles of radii 1,2,...,n around a central circle: a Supnick TSP and certified finite optima

We study a discrete-geometric optimization problem: circles of radii $1,2,\dots,n$ are all externally tangent to a central circle, and the central radius $R$ is minimized over cyclic orders of the surrounding circles. We prove that the chain-ordering component is governed by a fixed Supnick/anti-Monge traveling-salesman order. For every $R$, the angular-separation matrix is symmetric anti-Monge, so Supnick's theorem gives one minimizing cyclic order, independent of $R$. This proves the conjectured "pyramid" order optimal whenever the corresponding chain necklace is geometrically realizable, and gives an unconditional lower bound in all cases. Full geometric feasibility can fail because non-adjacent circle constraints are not captured by the chain equation; from $n=8$ the smallest circle can become a floating circle tangent only to the central circle. We formulate the full problem as a circular system of pairwise angular constraints, equivalently a simple temporal network, and certify global optima for $3\le n\le14$ using branch-and-bound plus an independent 50-digit verifier. We observe heuristically that the floating-circle cascade continues beyond the certified range, and we state the continuation and the asymptotic form $R^\ast(n)=n^2/8(1+o(1))$ as conjectures. The repository contains the saved certificate artifacts, verifier, and reproducibility commands.

cs.CG