Open problems submitted to the 2nd Canadian Discrete and Algorithmic Mathematics Conference will be held on May 25-28, 2009, at the Centre de recherches mathématiques in Montréal, Canada. put brief summary here Comments and questions of a technical nature about a particular problem should be sent to the correspondent for that problem. Please send other comments and information about partial or ...

The concept of geometric−arithmetic indices (GA) was put forward in chemical graph theory very recently. In spite of this, several works have already appeared dealing with these indices. In this paper we present lower and upper bounds on the second geometric−arithmetic index (GA2) and characterize the extremal graphs. Moreover, we establish Nordhaus−Gaddum−type results for GA2.

The authors Miličević et al. introduced the reformulated Zagreb indices [1], which is a generalization of classical Zagreb indices of chemical graph theory. In this paper, we mainly consider the maximum and minimum for the first reformulated index of graphs with connectivity at most k. The corresponding extremal graphs are characterized.

The integral circulant graph Xn(D) has the vertex set Zn = {0, 1, 2, . . . , n − 1} and vertices a and b are adjacent, if and only if gcd(a − b, n) ∈ D, where D = {d1, d2, . . . , dk} is a set of divisors of n. These graphs play an important role in modeling quantum spin networks supporting the perfect state transfer and also have applications in chemical graph theory. In this paper, we deal wi...