The stable Adams conjecture and higher associative structures on Moore spectra

Abstract: In this paper, we provide a new proof of the stable Adams conjecture. Our proof constructs a canonical null-homotopy of the stable J-homomorphism composed with a virtual Adams operation, by applying the $\mathrm{K}$-theory functor to a multi-natural transformation. We also point out that the original proof of the stable Adams conjecture is incorrect and present a correction. This correction is crucial to our main application. We settle the question on the height of higher associative structures on the mod $p^k$ Moore spectrum $\mathrm{M}_p(k)$ at odd primes. More precisely, for any odd prime $p$, we show that $\mathrm{M}_p(k)$ admits a Thomified $\mathbb{A}_n$-structure if and only if $n < p^k$. We also prove a weaker result for $p=2$.