Computations of relative topological coHochschild homology

Abstract: Hess and Shipley defined an invariant of coalgebra spectra called topological coHochschild homology, and Bohmann-Gerhardt-H{\o}genhaven-Shipley-Ziegenhagen developed a coB\"okstedt spectral sequence to compute the homology of coTHH for coalgebras over the sphere spectrum. We construct a relative coB\"okstedt spectral sequence to study coTHH of coalgebra spectra over any commutative ring spectrum $R$. Further, we use algebraic structures in this spectral sequence to complete some calculations of the homotopy groups of relative topological coHochschild homology.