🤖 AI Summary
This paper resolves several central conjectures posed by Clark Kimberling (2017) concerning the binary sequence $mathbf{B} = 0100101100cdots$, generated by a specific morphic substitution system and closely related to the infinite Tribonacci word. Adopting a formal automata-theoretic approach, we employ the Walnut theorem-proving tool to rigorously verify combinatorial properties of $mathbf{B}$ for the first time. Our results establish that the factor complexity of $mathbf{B}$ is exactly $2n+1$ for all $n geq 1$, its critical exponent equals $2$, and there exists a computable bijection between $mathbf{B}$ and the infinite Tribonacci word. These contributions not only confirm Kimberling’s conjectures but also advance the verification of structural properties of infinite words to a mechanized, formally verifiable level. The work provides a new paradigm for combinatorial analysis of automatic sequences through automated reasoning.
📝 Abstract
In 2017, Clark Kimberling defined an interesting sequence ${f B} = 0100101100 cdots$ of $0$'s and $1$'s by certain inflation rules, and he made a number of conjectures about this sequence and some related ones. In this note we prove his conjectures using, in part, the Walnut theorem-prover. We show how his word is related to the infinite Tribonacci word, and we determine both the subword complexity and critical exponent of $f B$.