$\mathrm{H}\mathbb{F}_2$-synthetic homotopy groups of topological modular forms

Abstract

To any Adams-type spectrum $E$, Pstr\k{a}gowski produced a symmetric monoidal stable $\infty$-category $Syn_E$ whose objects are, in a sense, ''formal Adams spectral sequences''. $Syn_E$ comes equipped with a lax symmetric monoidal functor $\nu_E:Sp\to Syn_E$ from classical spectra, which embeds $Sp$ fully and faithfully in $Syn_E$, and is a category with a natural notion of bigraded homotopy groups. The bigraded homotopy groups $\pi_{*,*}\nu_EX$ systematically record information about the homotopy groups $\pi_*X$ and the $E$-Adams spectral sequence of $X$. In this paper, we compute the $\nu_{\mathrm{H}\mathbb{F}_2}\mathbb{F}_2$-Adams spectral sequence of $\nu_{\mathrm{H}\mathbb{F}_2}tmf_2^{\wedge}$, synthetic versions of hidden $2$-, $\eta$-, $\nu$-, and $\overline{\kappa}$-extensions, and use this to deduce information about the homotopy ring structure of $\pi_{*,*}\nu_{\mathrm{H}\mathbb{F}_2}tmf_2^{\wedge}$.