Dear Joachim, After perusing the proposed changes, I offer some possible additions, which I list for your consideration. 18C15. Add "Distributions and Distribution Algebras" 18D25. Add "Lax Functors, Lax Adjointness" 18D30. Add "Complete Spreads over Generalized Spaces" 18E50. Add "Fundamental Groupoids for Generalized Spaces" 18F40. Add or Insert "Synthetic Differential Topology". I can add some justifications if need be. Best regards, Marta ________________________________ From: Joachim Kock <kock@mat.uab.cat> Sent: August 1, 2018 8:32:50 AM To: categories@mta.ca Subject: categories: MSC2020, Section 18 Dear all, the Mathematics Subject Classification will soon be revised by Mathematical Reviews and Zentralblatt, aiming at a new edition, MSC2020. They are soliciting suggestions and feedback until August 8th. Three of us (Emily Riehl, Steve Lack, Joachim Kock) have been collaborating on a proposal for Section 18 (Category theory; homological algebra). The main point of the proposal is to create new subsections 18H Higher categories and homotopical algebra 18M Monoidal categories and operads, big subfields of category theory where it is particularly difficult to find good entries in the MSC2010. We also take the opportunity to propose some adjustments in the existing subsections of 18. The proposed new Section 18 is included below in plain text. A more detailed document, with change comments, can be accessed at this link: https://www.dropbox.com/s/yr400e893uhhctm/MSC2020.pdf?dl=0 We are still fine-tuning the proposal. Before submitting the proposal (one week from now), we would like to request last-minute feedback from the category theory community, either on this mailing list or in private. We also invite you to co-sign the proposal. We are sorry for getting this proposal out so late. But this is only the starting point: the next phase in the timeline set out by MR and zbMATH is 12 months of community feedback, so there will still be plenty of time for discussion. Best wishes, Emily Riehl, Joachim Kock, Steve Lack. [For admin and other information see: http://www.mta.ca/~cat-dist/ ]