{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,7,30]],"date-time":"2025-07-30T16:43:01Z","timestamp":1753893781962,"version":"3.41.2"},"reference-count":0,"publisher":"The Electronic Journal of Combinatorics","issue":"1","content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Electron. J. Combin."],"abstract":"<jats:p>A mixed hypergraph is characterized by the fact that it possesses ${\\cal C}$-edges as well as ${\\cal D}$-edges. In a colouring of a mixed hypergraph, every ${\\cal C}$-edge has at least two vertices of the same colour and every ${\\cal D}$-edge has at least two vertices coloured differently. The upper and lower chromatic numbers $\\bar{\\chi}$, $\\chi$ are the maximum and minimum numbers of colours for which there exists a colouring using all the colours. The concepts of mixed hypergraph, upper and lower chromatic numbers are applied to $SQSs$. In fact a BSQS is an SQS where all the blocks are at the same time ${\\cal C}$-edges and ${\\cal D}$-edges. In this paper we prove that any $BSQS(16)$ is colourable with the upper chromatic number $\\bar{\\chi}=3$ and we give new information about the chromatic spectrum of BSQSs($16$).<\/jats:p>","DOI":"10.37236\/1550","type":"journal-article","created":{"date-parts":[[2020,1,10]],"date-time":"2020-01-10T21:09:46Z","timestamp":1578690586000},"source":"Crossref","is-referenced-by-count":3,"title":["On the Upper and Lower Chromatic Numbers of BSQSs(16)"],"prefix":"10.37236","volume":"8","author":[{"given":"Giovanni Lo","family":"Faro","sequence":"first","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Lorenzo","family":"Milazzo","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Antoinette","family":"Tripodi","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"23455","published-online":{"date-parts":[[2000,10,20]]},"container-title":["The Electronic Journal of Combinatorics"],"original-title":[],"link":[{"URL":"https:\/\/www.combinatorics.org\/ojs\/index.php\/eljc\/article\/download\/v8i1r6\/pdf","content-type":"application\/pdf","content-version":"vor","intended-application":"text-mining"},{"URL":"https:\/\/www.combinatorics.org\/ojs\/index.php\/eljc\/article\/download\/v8i1r6\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2020,1,18]],"date-time":"2020-01-18T00:21:39Z","timestamp":1579306899000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.combinatorics.org\/ojs\/index.php\/eljc\/article\/view\/v8i1r6"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2000,10,20]]},"references-count":0,"journal-issue":{"issue":"1","published-online":{"date-parts":[[2001,1,1]]}},"URL":"https:\/\/doi.org\/10.37236\/1550","relation":{},"ISSN":["1077-8926"],"issn-type":[{"type":"electronic","value":"1077-8926"}],"subject":[],"published":{"date-parts":[[2000,10,20]]},"article-number":"R6"}}