QUESTION: What are the major or systematic applications of post-1960s mathematics to microeconomics?
For example, in the late 19th century, Fisher first used the mathematical ideas of Gibbs to construct modern utility theory. In the 20th century, Mas-Colell incorporated topological ideas to study general equilibrium. What about the late 20th, early 21st century?
For example, consider directed graph theory, measure theory, topology, the category theory and modern homology or cohomology, topos methods, functional integration, etc.
Note 1: econometrics/statistics, without modelling, is excluded. The only modern mathematics used there is random walk theory, and the ergodic problem, solved via complex analysis. RW and EP are not specific to economics.
Any appropriate economics publication is an answer. This included also those published in non-strictly economics journals, e.g. the Journal of Mathematical Psychology.
Note 2: Yes, I know, this type of work is rarer (not to be confused with obscurity: some of it is well known). That is what makes it easy to miss such a reference when it is published. Hence the question.