fact: Definition codeleft2plus := {yqqu : codeleft2 & Join ((x0; codeleft2_q00 yqqu) = (x1; codeleft2_q10 yqqu) :> {x:X & Q x (codeleft2_y0 yqqu)}) ((codeleft2_y0 yqqu; codeleft2_q10 yqqu) = (y1; q11) :> {y:Y & Q x1 y})}.
imports: HoTT.Basics HoTT.Types Colimits.Pushout Colimits.SpanPushout Homotopy.Join.Core Truncations