We introduce tropical complexes, as an enrichment of the dual complex of a degeneration with additional data from non-transverse intersection numbers. We define cycles, divisors, and linear equivalence on tropical complexes, analogous both to the corresponding theories on algebraic varieties and to work on graphs and tropical curves. In addition, we establish conditions for the divisor-curve intersection numbers on a tropical curve to agree with the generic fiber of a degeneration. 'd especially like to thank Sam Payne for his many insightful suggestions and thoughtful comments on an early draft of this paper. I was supported by the National Science Foundation award number DMS-1103856 and National Security Agency award H98230-16-1-0019. I would also like to acknowledge the hospitality of the University of Georgia, where the first round of revisions to this paper were done.
Degenerations and their tropical complexesThis section defines tropical complexes as combinatorial objects and to explains their construction from a degeneration. We begin by discussing the combinatorial properties of degenerations.We use degeneration to refer to a regular scheme X which is flat and proper over a discrete valuation ring R, and such that the special fiber X 0 is a reduced simple normal crossing divisor. In addition, we always assume that the residue field of the discrete valuation ring R is algebraically closed.