{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,7,30]],"date-time":"2025-07-30T16:44:28Z","timestamp":1753893868373,"version":"3.41.2"},"reference-count":0,"publisher":"The Electronic Journal of Combinatorics","issue":"2","content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Electron. J. Combin."],"abstract":"<jats:p>We introduce some new classes of words and permutations characterized by the second difference condition $\\pi(i-1) + \\pi(i+1) - 2\\pi(i) \\leq k$, which we call the $k$-convexity condition. We demonstrate that for any sized alphabet and convexity parameter $k$, we may find a generating function which counts $k$-convex words of length $n$. We also determine a formula for the number of 0-convex words on any fixed-size alphabet for sufficiently large $n$ by exhibiting a connection to integer partitions. For permutations, we give an explicit solution in the case $k = 0$ and show that the number of 1-convex and 2-convex permutations of length $n$ are $\\Theta(C_1^n)$ and $\\Theta(C_2^n)$, respectively, and use the transfer matrix method to give tight bounds on the constants $C_1$ and $C_2$. We also providing generating functions similar to the the continued fraction generating functions studied by Odlyzko and Wilf in the \"coins in a fountain\" problem.<\/jats:p>","DOI":"10.37236\/5396","type":"journal-article","created":{"date-parts":[[2020,1,10]],"date-time":"2020-01-10T16:23:27Z","timestamp":1578673407000},"source":"Crossref","is-referenced-by-count":0,"title":["Locally Convex Words and Permutations"],"prefix":"10.37236","volume":"23","author":[{"given":"Christopher","family":"Coscia","sequence":"first","affiliation":[]},{"given":"Jonathan","family":"DeWitt","sequence":"additional","affiliation":[]}],"member":"23455","published-online":{"date-parts":[[2016,4,15]]},"container-title":["The Electronic Journal of Combinatorics"],"original-title":[],"link":[{"URL":"https:\/\/www.combinatorics.org\/ojs\/index.php\/eljc\/article\/download\/v23i2p10\/pdf","content-type":"application\/pdf","content-version":"vor","intended-application":"text-mining"},{"URL":"https:\/\/www.combinatorics.org\/ojs\/index.php\/eljc\/article\/download\/v23i2p10\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2020,1,17]],"date-time":"2020-01-17T00:30:10Z","timestamp":1579221010000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.combinatorics.org\/ojs\/index.php\/eljc\/article\/view\/v23i2p10"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2016,4,15]]},"references-count":0,"journal-issue":{"issue":"2","published-online":{"date-parts":[[2016,3,31]]}},"URL":"https:\/\/doi.org\/10.37236\/5396","relation":{},"ISSN":["1077-8926"],"issn-type":[{"type":"electronic","value":"1077-8926"}],"subject":[],"published":{"date-parts":[[2016,4,15]]},"article-number":"P2.10"}}