An Improved Lower Bound for the Traveling Salesman Constant

Abstract: Let $X_1, X_2, \dots, X_n$ be independent uniform random variables on $[0,1]^2$. Let $L(X_1, \dots, X_n)$ be the length of the shortest Traveling Salesman tour through these points. It is known that there exists a constant $\beta$ such that $$\lim_{n \to \infty} \frac{L(X_1, \dots, X_n)}{\sqrt{n}} = \beta$$ almost surely (Beardwood 1959). The original analysis in (Beardwood 1959) showed that $\beta \geq 0.625$. Building upon an approach proposed in (Steinerberger 2015), we improve the lower bound to $\beta \geq 0.6277$.