0 KB222 KB23 KB200820252012Pinto, Danielštevilka:2letnik:5str. 259-267COBISSID:16275545ISSN:1855-3966URN:URN:NBN:SI:doc-SXOV5L0NenDruštvo matematikov, fizikov in astronomov SlovenijeArs mathematica contemporaneaalternating groupdualitydualnostgeneratorjigeneratorsgraph theorygrupeprimitive groupsymmetric groupteorija grafovDuality on hypermaps with symmetric or alternating monodromy group|Duality is the operation that interchanges hypervertices and hyperfaces on oriented hypermaps. The duality index measures how far a hypermap is from being self-dual. We say that an oriented regular hypermap has duality-type ?$\{l, n\}$? if ?$l$? is the valency of its vertices and ?$n$? is the valency of its faces. Here, we study some properties of the duality index of oriented regular hypermaps and we prove that for each pair ?$n, l \in \mathbb{N}$?, with ?$n, l \ge 2$? (but not both equal to 2), it is possible to find an oriented regular hypermap with extreme duality index and of duality-type ?$\{l, n\}$?, even if we are restricted to hypermaps with alternating or symmetric monodromy groupTEXTznanstveno časopisjejournalsSlovenian National E-content AggregatorNational and University Library of SloveniaUniverza na Primorskem, Fakulteta za naravoslovje, matematiko in informacijske tehnologije