The universal logic of repeated experiments
Sergio Daniel Grillo
TL;DR
The article develops a universal framework for the event space of repeated experiments beyond classical Boolean logic. It constructs the universal logic $\mathsf{U}_{\kappa}(\mathsf{E})$ from a given complete orthocomplemented lattice $\mathsf{E}$, embedding $\mathsf{E}^{\kappa}$ and closing under a closure operator to obtain a complete, distributive lattice that preserves the original logic’s distributivity. A key result is that $\mathsf{U}_{\kappa}(\mathsf{E})$ is distributive iff $\mathsf{E}$ is distributive, and that there exists a natural epimorphism from $\mathsf{U}_{\kappa}(\mathsf{E})$ onto the Boolean algebra generated by $\mathsf{E}^{\kappa}$, $\langle \mathsf{E}^{\kappa} \rangle$, linking the universal construction to classical multi-shot experiments. The paper also extends the framework to nonuniform repetitions via tensor products $\bigotimes_{\alpha\in\kappa} \mathsf{E}_{\alpha}$ and provides a universal property characterizing these constructions, enabling a broad applicability to quantum and classical logics alike.
Abstract
Let $\mathsf{E}$ be the event space of an experiment that can be indefinitely repeated, in such a way that the result of one repetition does not affect the result of the other. A natural question arises: given a countable cardinal $κ$, which is the event space of the $κ$-times repeated experiment? In the case of classical experiments, where $\mathsf{E}$ is a (complete) Boolean algebra on some set $S$, i.e. a \textit{classical }or\textit{ distributive logic}, the answer is more and less known: the (complete) Boolean algebra on $S^κ$ generated by $\mathsf{E}^κ$. But, what if $\mathsf{E}$ is not a Boolean algebra? In this paper we give a constructive answer to this question for any $κ$ and in the context of general orthocomplemented complete lattices, i.e. \textit{general logics}. Concretely, given a general logic $\mathsf{E}$ defining the event space of a given experiment, we construct a logic $\mathsf{U}_κ\left(\mathsf{E}\right)$ representing the event space of the $κ$-times repeated experiment, in such a way that $\mathsf{U}_κ\left(\mathsf{E}\right)$ and $\mathsf{E}$ are isomorphic if $κ=1$, and such that $\mathsf{U}_κ\left(\mathsf{E}\right)$ is distributive if and only if so is $\mathsf{E}$. We also extend our construction to the case in which the event space changes from one repetition to another and the cardinal $κ$ is arbitrary. This gives rise to tensor products $\bigotimes_{α\inκ}\mathsf{E}_α$ of families $\left\{ \mathsf{E}_α\right\} _{α\inκ}$ of orthocomplemented complete lattices, in terms of which $\mathsf{U}_κ\left(\mathsf{E}\right)=\bigotimes_{α\inκ}\mathsf{E}$.
