Let X be the Hankel matrix of size 2Γn and let G be a closed
graph on the vertex set [n]. We study the binomial ideal IGββK[x1β,β¦,xn+1β] which is generated by all the 2-minors of X which
correspond to the edges of G. We show that IGβ is Cohen-Macaulay. We find
the minimal primes of IGβ and show that IGβ is a set theoretical complete
intersection. Moreover, a sharp upper bound for the regularity of IGβ is
given