Immersions and translation structures I: The space of structures on the pointed disk

We define a moduli space of translation structures on the open topological disk with a basepoint and endow it with a locally-compact metrizable topology. We call this the immersive topology, because it is defined using the concept of immersions: continuous maps between subsets of translation surfaces that respect the basepoints and the translation structures. Immersions induce a partial ordering on the moduli space, and we prove the ordering is nearly a complete lattice in the sense of order theory: The space is only missing a minimal element. Subsequent articles will uncover more structure and develop a topology on the space of all translation structures.