Tropicalization of Canonical Curves: the Planar Case

We study a topological version of the tropical lifting problem for canonical curves. This leads us to a tropical analogue of the notion of graph curves that we refer to as tropical graph curves. We study the analogous tropical lifting problem for graph curves and use this as a tool to show that every three regular, three edge connected planar graph of a given genus can be realized as the tropicalization of a canonical curve of the same genus.Comment: 26 pages, 14 Figures. This Is a revised version of our preprint "Tropical Graph Curves". We have completely rewritten the introduction, revised the body of the paper including several proofs and added a new section "Conclusion and Future Work

Total Semirelib Graph

In this paper, the concept of Total semirelib graph of a planar graph is introduced. Authors present a characterization of those graphs whose total semirelib graphs are planar, outer planar, Eulerian, hamiltonian with crossing number one

Monomials, Binomials, and Riemann-Roch

The Riemann-Roch theorem on a graph G is related to Alexander duality in combinatorial commutive algebra. We study the lattice ideal given by chip firing on G and the initial ideal whose standard monomials are the G-parking functions. When G is a saturated graph, these ideals are generic and the Scarf complex is a minimal free resolution. Otherwise, syzygies are obtained by degeneration. We also develop a self-contained Riemann-Roch theory for artinian monomial ideals.Comment: 18 pages, 2 figures, Minor revision

On Distributed Computation in Noisy Random Planar Networks

We consider distributed computation of functions of distributed data in random planar networks with noisy wireless links. We present a new algorithm for computation of the maximum value which is order optimal in the number of transmissions and computation time.We also adapt the histogram computation algorithm of Ying et al to make the histogram computation time optimal.Comment: 5 pages, 2 figure

Tutte Short Exact Sequences of Graphs

We associate two modules, the $G$-parking critical module and the toppling critical module, to an undirected connected graph $G$. We establish a Tutte-like short exact sequence relating the modules associated to $G$, an edge contraction $G/e$ and edge deletion $G \setminus e$ ($e$ is a non-bridge). As applications of these short exact sequences, we relate the vanishing of certain combinatorial invariants (the number of acyclic orientations on connected partition graphs satisfying a unique sink property) of $G/e$ to the equality of corresponding invariants of $G$ and $G \setminus e$. We also obtain a short proof of a theorem of Merino that the critical polynomial of a graph is an evaluation of its Tutte polynomial.Comment: 40 pages, 3 figure