5 papers
Asymptotics of the Tchoukaillon array and a conjecture of Beluhov
Shisheng Li
The Tchoukaillon array is an infinite array of the positive integers, arising from a one-row Mancala solitaire, in which each positive integer occurs exactly once. Its zeroth colum…
Every natural number is a sum of distinct semiprime unit fractions
Shisheng Li
We prove that every natural number is a finite sum of distinct unit fractions whose denominators are semiprimes (products of two distinct primes). This is the integer case of…
Nonexistence of Whirling-Knight Tours at Half Coil Count for
Shisheng Li
A whirling knight's tour is a Hamiltonian cycle in the digraph of counter-clockwise knight steps about the centre of an board; its coil count is the winding number…
has no Hamiltonian cycle when is even: a sign-of-permutation proof, with extension to all odd
Shisheng Li
We resolve exercise 7.2.2.4--224 of Knuth's Pre-Fascicle 8a (10 April 2026 draft, rated [46]): the digraph has no Hamiltonian cycle when is even. The argumen…
A note on the parameter in Buchbinder--Feldman's deterministic submodular matroid algorithm
Shisheng Li
Buchbinder and Feldman recently gave a deterministic -approximation for maximizing a non-negative monotone submodular function subject to a matroid constraint,…