Subjective expected utility on orthomodular lattices

In recent work, the author has developed a general category-theoretic framework for decision theory. This article applies this to the category of orthomodular lattices (OMLs). Every Boolean algebra is an OML, so this yields a new (syntactic) model of decision-making with classical uncertainty. The lattice of closed subspaces of a Hilbert space is also an OML, so this also yields a new model of decision-making with quantum uncertainty. This article is part of the theme issue 'Quantum theory and topology in models of decision making (Part 2)'.