In independent component analysis, prior information on the distributions of the independent components is often used; some weak information is in fact necessary for succesful estimation. In contrast, prior information on the mixing matrix is usually not used. This is because it is considered that the estimation should be completely blind as to the form of the mixing matrix. Nevertheless, it co...

A graph is well-covered if every maximal independent set has the same cardinality, namely the vertex independence number. We answer a question of Topp and Volkmann [5] and prove that if the Cartesian product of two graphs is well-covered, then at least one of them must be well-covered.

In independent component analysis, prior information on the distributions of the independent components is often used; some weak information may in fact be necessary for successful estimation. In contrast, prior information on the mixing matrix is usually not used. This is because it is considered that the estimation should be completely blind as to the form of the mixing matrix. Nevertheless, ...