@article {IOPORT.05556431,
    author       = {Fredricks, Gregory A.},
    title        = {A conjecture of Bertino: from copulas to graph theory.},
    year         = {2008},
    journal      = {Acta et Commentationes Universitatis Tartuensis de Mathematica},
    volume       = {12},
    issn         = {1406-2283},
    pages        = {17-30},
    publisher    = {University of Tartu, Faculty of Mathematics and Computer Science, Tartu},
    abstract     = {A copula is a function $c$ from the unit square to the unit interval with boundary values 0 at all $(t,0)$ and $(0,t)$, boundary values $t$ at all $(t,1)$ and $(1,t)$, and having non-negative values $c(s,t)-c(s,v)-c(u,t)+c(u,v)$ for all $s<u$ and $t<v$ in the unit interval. The double increment is called the $c$-volume of the rectangle $[s,u]\times[t,v]$. The $c$-volume of the rectangle $[t,t+1/2]\times[t,t+1/2]$ integrated for $0<t<1/2$ is a function $F(c)$ of the copula $c$. A conjecture of Bertino about the minimum value of $F$ in a space of copulas is here interpreted and proved by using concepts from graph theory.},
    reviewer     = {Ove Frank (Stockholm)},
    identifier   = {05556431},
}