caa a22 4500 475778162 CHVBK 20180406123636.0 cr unu---uuuuu 170329e20001201xx s 000 0 eng 10.1007/PL00007226 doi (NATIONALLICENCE)springer-10.1007/PL00007226 Colour Number, Capacity, and Perfectness of Directed Graphs [Elektronische Daten] [Emanuela Fachini, János Körner] Abstract.: We introduce a new concept of chromatic number for directed graphs, called the colour number and use it to upper bound the transitive clique number and the Sperner capacity of arbitrary directed graphs. Our results represent a common generalization of previous bounds of Alon and the second author and lead to a concept of perfectness for directed graphs. Springer-Verlag Tokyo, 2000 Fachini Emanuela Department of Computer Science, La Sapienza University of Roma, via Salaria 113, 00198 Roma, Italy e-mail: fachini@dsi.uniromal.it, IT aut Körner János Department of Computer Science, La Sapienza University of Roma, via Salaria 113, 00198 Roma, Italy e-mail: korner@dsi.uniroma1.it, IT aut https://doi.org/10.1007/PL00007226 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/PL00007226 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Fachini Emanuela Department of Computer Science, La Sapienza University of Roma, via Salaria 113, 00198 Roma, Italy e-mail: fachini@dsi.uniromal.it, IT aut NATIONALLICENCE 700 1- Körner János Department of Computer Science, La Sapienza University of Roma, via Salaria 113, 00198 Roma, Italy e-mail: korner@dsi.uniroma1.it, IT aut Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer