@GijsHeuts Actually the paper you linked to seems to be answering the converse question: i.e. when Σ Tot(Y) is equivalent to Y as an associative comonoid. This seem to imply the statement I was after (Tot(ΣX)=X) for X 1-connected, but I'm wondering if it holds more generally
I don't really understand the picture of A(2)/Sq^1, or maybe I don't know what it means. If it's the quotient by the 2-sided ideal generated by Sq^1, then maybe it's okay, but not if it's the quotient by the left ideal generated by Sq^1 (which is what skd is looking for).
yeah, i don't think that drawing answers my question sadly. as you said i'm interested in A(2)/A(2)*Sq^1 (so it's not given by that diagram since it isn't 32-dimensional)
but with some tedious work i can deduce the drawing from the bruner-johnson interactive diagram