Towards a General Theory of Dependent Sums

Abstract

We introduce dependent adders. A dependent adder $A$ has for every $x\in A$ a way of adding together $x$ many elements of $A$. We provide examples from many disparate branches of mathematics. Examples include the field with one element ${\mathbb{F}}_1$, the real numbers with integrals as sums, the category of categories with oplax colimits as sums. We also consider modules over dependent adders and provide examples.