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Axis-Parallel Square Packing


Axis-parallel square packing is the problem of placing squares with prescribed side lengths in a square container with disjoint interiors and sides parallel to those of the container. Unlike square packing of congruent squares with unrestricted orientations, the sizes here may differ and rotations are not allowed. Let L_n^*(s) be the least possible container side for nonnegative side lengths s_0>=s_1>=...>=s_(n-1) (Badger 2026a).

Badger (2026a) gave exact formulas through seven squares. For six,

 L_6^*(s)=max(s_0+s_1,s_2+s_3+s_4,s_1+s_4+s_5).

For seven,

 L_7^*(s)=max(L_6^*(s),min{max(s_3+s_4+s_5+s_6,s_1+s_2+s_5),max(s_0+s_5+s_6,s_1+s_3+s_6),s_1+s_4+s_5+s_6}).

More generally, for n>=6 the optimum is a sum of at most n-3 prescribed side lengths, and this bound is sharp on an open set of side vectors (Badger 2026a). Badger (2026a) credits Claude with implementing exact searches and assisting the development of the lower-bound arguments, and Claude and ChatGPT with reviewing the mathematics. The author states that he checked all proofs.

Badger (2026b) extended the exact optimization to eight prescribed squares. The optimum is the minimum of 23 explicit convex strategy-cost functions. Moreover, it cannot be expressed as the minimum of fewer than 23 convex functions. Thus the minimum complete strategy-family sizes for six, seven, and eight squares are 1, 3, and 23, respectively. Badger (2026b) reports AI assistance with the search for the formula, development of lower bounds, and exact verification of the constructions and certificates.


See also

Packing, Square, Square Packing

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References

Badger, M. "Axis-Parallel Square Packing with an Exact Formula for Optimal Packing of Seven Squares." 15 Oct 2026a. https://arxiv.org/abs/2610.22622.Badger, M. "An Exact Formula for Optimal Axis-Parallel Packing of Eight Squares." 20 Oct 2026b. https://arxiv.org/abs/2610.28504.

Cite this as:

Weisstein, Eric W. "Axis-Parallel Square Packing." From MathWorld--A Wolfram Resource. https://mathworld.wolfram.com/Axis-ParallelSquarePacking.html

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