Impressed by the elegance and simplicity of the Popov frequency criterion and the concept of hyperstability, I have joined in October 1967 (for one year) the group of V.M. Popov at the Energy Institute of the Romanian Academy with the objective to apply the Popov theory to adaptive systems and real-time identification. From the interpretation of the Popov stability criterion in terms of an equi...

The Popov Prize honors the memory of Vasil A. Popov (19421990), the Bulgarian analyst best known for his work in Nonlinear Approximation. The Prize is awarded every third year to a young mathematician (less than six years removed from the Ph.D.) for outstanding research contributions to Approximation Theory and/or related areas. Previous Popov Prize winners are Albert Cohen (Paris), Arno Kuijla...

SUMMA R Y. In the Dahomeyan of the western Accra Plains marie gneisses, amphibolites, and orthoamphibolite dykes in granitic gneiss occur. During the latest recrystallization, metamorphic conditions ranged (north to south) from oligoclase--epidote amphibolite subfacies through andesineepidote amphibolite subfacies to at least the medium or upper part of the amphibolite facies. Chemical analyses...