Table Of Content

TOPOLOGICAL, ALGEBRAICAL AND COMBINATORIAL STRUCTURES FROLIK’S MEMORIAL VOLUME Guest Editor: J. NeSetfil CONTENTS Preface PART |. GEOMETRY AND TOPOLOGY B. Balcar and P. Simon Reaping number and z-character of Boolean algebras A. Fedeli, J. Reiterman and A. Tozzi On w,-compactness A. Fernandez and V. Miller Embedding of a separable locally pseudoconvex algebra into a locally pseudoconvex algebra with two generators J. Gerlits, A.H ajnal and Z. Szentmikléssy On the cardinality of certain Hausdorff spaces J. Gil, W. Steiger and A. Wigderson Geometric medians T. Jech The logarithmic distribution of leading digits and finitely additive measures I. KFiz All trapezoids are Ramsey J. Paseka Products in the category of locales: which properties are preserved? J. Pelant and V. Rédl On coverings of infinite-dimensional metric spaces H.J. Prémel and B. Voigt From wao to bqo, via Ellentuck’s theorem A. Pultr Notes on an extension of the structure of frame P. Valtr Sets in R“ with no large empty convex subsets P. Vojtas Cardinalities of noncentered systems of subsets of w PART Il. STRUCTURES AND ALGEBRA 131 J. Adamek and J. Rosicky On orthogonal subcategories of locally presentable categories 133 A. Bjérner and J. Karlander Invertibility of the base Radon transform of a matroid 139 M. Fiedler An extremal problem for the spectral radius of a graph 149 W. Imrich and J. NeSetfil Simple tournaments and sharply transitive groups 159 H. Maehara Extending a flexible unit-bar framework to a rigid one 167 V. Ptak Thickness of families of sets and a minimax lemma 175 A. Recski Applications of combinatorics to statics—a second survey 183 J. Sirah and M. Skoviera Groups with sign structure and their antiautomorphisms 189 V. Trnkova Endomorphisms of undirected modifications of directed graphs 203 J. Vinarek Simultaneous representations of groups 211 PART Ill. COMBINATORICS 217 R. Adamec, M. Klazar and P. Valtr Generalized Davenport—Schinzel sequences with linear upper bound 219 L.D. Andersen The strong chromatic index of a cubic graph is at most 10 231 P. Bugata Trahtenbrot—Zykov problem and NP-completeness 253 R.A. Duke, P. Erdés and V. Rédl Cycle-connected graphs 261 P. Erd6és, T. Gallai and Zs. Tuza Covering the cliques of a graph with vertices 279 . P. Frankl On cross-intersecting families 291 P. Hell and D.J. Miller Achromatic numbers and graph operations 297 S. Janson and J. Kratochvil Thresholds for classes of intersection graphs 307 J. Jirasek . Some remarks on Adam's conjecture for simple directed graphs M. Loebl Unprovable combinatorial statements J. MatouSek and R. Thomas On the complexity of finding iso- and other morphisms for partial k-trees M. Middendorf and F. Pfeiffer The max clique problem in classes of string-graphs V. Nyal Finite undirected graphs which are not reconstructible from their large cardinality subgraphs S. Poljak and D. Turzik Max-cut in circulant graphs A.A. Razborov The gap between the chromatic number of a graph and the rank of its adjacency matrix is superlinear Zs. Tuza Asymptotic growth of sparse saturated structures is locally determined Author index to volume 108