$L^2$ Fr\"olicher inequalities

We prove a Fr\"olicher inequality between $L^2$ Betti and $L^2$ Hodge numbers on normal coverings of compact complex manifolds. This is achieved by building an injection using suitable spectral projectors associated to the self adjoint operators $(D_h)^2:=(\overline\partial+\overline\partial^*+h\partial+h\partial^*)^2$ for $h\in[0,1]$. As a by-product, we find a new proof of the classical Fr\"olicher inequality on compact complex manifolds which does not rely at all on spectral sequences.