The paper where they introduce subsumption is "Michael Codish, Luís Cruz-Filipe,...

		jix on May 6, 2021 \| parent \| context \| favorite \| on: Proving 50-Year-Old Sorting Networks Optimal: Part... The paper where they introduce subsumption is "Michael Codish, Luís Cruz-Filipe, Michael Frank, and Peter Schneider-Kamp. 2016. Sorting nine inputs requires twenty-five comparisons. Journal of Computer and System Sciences 82, 3 (May 2016), 551–563." and I just realized that I lost the actual citation while editing my blog post, fixed that now.

Thanks. I thought there was a citation missing! I'll have a look at the paper.