{ "id": "1801.04555", "version": "v1", "published": "2018-01-14T13:34:30.000Z", "updated": "2018-01-14T13:34:30.000Z", "title": "Remarks on Graphons", "authors": [ "Attila Nagy" ], "comment": "11 pages", "categories": [ "math.CO" ], "abstract": "The notion of the graphon (a symmetric measurable fuzzy set of $[0, 1]^2$) was introduced by L. Lov\\'asz and B. Szegedy in 2006 to describe limit objects of convergent sequences of dense graphs. In their investigation the integral \\[t(F,W)=\\int _{[0, 1]^k}\\prod _{ij\\in E(F)}W(x_i,x_j)dx_1dx_2\\cdots dx_k\\] plays an important role in which $W$ is a graphon and $E(F)$ denotes the set of all edges of a $k$-labelled simple graph $F$. In our present paper we show that the set of all fuzzy sets of $[0, 1]^2$ is a right regular band with respect to the operation $\\circ$ defined by \\[(f\\circ g)(s,t)=\\vee _{(x,y)\\in [0, 1]^2}(f(x,y)\\wedge g(s,t));\\quad (s, t)\\in [0, 1]^2,\\] and the set of all graphons is a left ideal of this band. We prove that, if $W$ is an arbitrary graphon and $f$ is a fuzzy set of $[0, 1]^2$, then \\[|t(F; W)-t(F; f\\circ W)|\\leq |E(F)|(\\sup(W)-\\sup(f))\\Delta (\\{W> \\sup(f)\\} )\\] for arbitrary finite simple graphs $F$, where $\\Delta (\\{W> \\sup(f)\\})$ denotes the area of the set $\\{W>\\sup(f)\\}$ of all $(x, y)\\in [0, 1]^2$ satisfying $W(x,y)>\\sup(f)$.", "revisions": [ { "version": "v1", "updated": "2018-01-14T13:34:30.000Z" } ], "analyses": { "subjects": [ "08A75", "20M10", "05C99" ], "keywords": [ "arbitrary finite simple graphs", "symmetric measurable fuzzy set", "right regular band", "limit objects", "arbitrary graphon" ], "note": { "typesetting": "TeX", "pages": 11, "language": "en", "license": "arXiv", "status": "editable" } } }