We prove that taking "chains with coefficients in an separably closed field k of characteristic p" induces a fully faithful functor from p-complete, nilpotent spaces to $E_{\infty}$ -coalgebras over k. This removes finiteness assumptions from a theorem of Mandell. (jt. with Robert Burklund).
Links:
[1] https://www.mpim-bonn.mpg.de/taxonomy/term/39
[2] https://www.mpim-bonn.mpg.de/node/3444
[3] https://www.mpim-bonn.mpg.de/UHT