A counterexample to the φ-dimension conjecture

In 2005, the second author and Todorov introduced an upper bound on the finitistic dimension of an Artin algebra, now known as the phi-dimension. The phi-dimension conjecture states that this upper bound is always finite, a fact that would imply the finitistic dimension conjecture. In this paper, we present a counterexample to the phi-dimension conjecture and explain where it comes from. We also discuss implications for further research and the finitistic dimension conjecture.