Before revision:  The proposed framework allows to split the norms into proper seminormsand not only results in{\it   simpler (shorter) proofs of many stability results but also guides the construction of parameter robust norm-equivalent preconditioners.
After revision:  The proposed framework allows to split the norms into proper seminormsand not only results in{\it fitted simpler (shorter) proofs of many stability results but also guides the construction of parameter robust norm-equivalent preconditioners.