Progress in Mathematics

This volume contains five review articles, two in the Algebra part and three in the Geometry part, surveying the fields of cate- gories and class field theory, in the Algebra part, and of Finsler spaces, structures on differentiable manifolds, and packing, cover- ing, etc., in the Geometry part. The literature covered is primar- Hy that published in 1964-1967. Contents ALGEBRA CATEGORIES ............... . 3 M. S. Tsalenko and E. G. Shul'geifer 1. Introduction........... 3 2. Foundations of the Theory of Categories . . . . . 4 3. Fundamentals of the Theory of Categories . . . . . 6 4. Embeddings of Categories ... . . . . . . . . . . . . 14 5. Representations of Categories . . . . . . . . . . . . . 16 6. Axiomatic Characteristics of Algebraic Categories . . . . . . . . . . . . . . . . . . . . . . . . . . 18 7. Reflective Subcategories; Varieties. . . 20 8. Radicals in Categories . . . . . . . 24 9. Categories with Involution. . . . . . 29 10. Universal Algebras in Categories . 30 11. Categories with Multiplication . . . 34 12. Duality of Functors. .. ....... 37 13. Homotopy Theory . . . . .. ........... 39 14. Homological Algebra in Categories. . . . . . 41 15. Concrete Categories . . . . .. ......... 44 16. Generalizations.. . . . . . . 45 Literature Cited . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47 CLASS FIELD THEORY. FIELD EXTENSIONS. . . . . . . . 59 S. P. Demushkin 66 Literature Cited vii CONTENTS viii GEOMETRY 75 FINSLER SPACES AND THEIR GENERALIZATIONS ..