“…Before we introduce estimators for ω and f , we need to discuss identifiability of these parameters in the SBSSRmodel, that is, conditions when g determines them uniquely via g = m i=1 ω i f i . Although, deterministic finite alphabet instantaneous (linear) mixtures, i.e., σ = 0 in the SBSSR-model (4), received a lot of attention in the literature [66,53,72,21,42,36,58], a complete characterization of identifiability remained elusive and has been recently provided in [5], which will be briefly reviewed here as far as it is required for our purposes. Obviously, not every mixture g ∈ M in (2) is identifiable.…”