From fredrik.nordvall-forsberg at strath.ac.uk Tue Sep 16 14:18:32 2025 From: fredrik.nordvall-forsberg at strath.ac.uk (Fredrik Nordvall Forsberg) Date: Tue, 16 Sep 2025 14:18:32 +0100 Subject: [msp-interest] [MSP101] Planning meeting Message-ID: <7b06d4a7-3c99-4342-8f35-79d4e624ef1a@strath.ac.uk> Dear all, This Thursday after 4pm, we will have the MSP 101 planning meeting for the semester. If you want to give a talk, or want someone else to give a talk, or want someone to give a talk about a particular topic, this is your chance! We will also decide on a time slot for the seminar in the coming semester. If you cannot make the meeting, but still want any of the above, you can also contact me or someone else to act as your representative during the meeting. Online participation is also possible, of course. Pre-planning is also encouraged on Zulip https://spls.zulipchat.com/#narrow/channel/227686-UoS/topic/MSP101.20planning . Best wishes, Fred --------------------------------------------------------- Date and time: Thursday 18 September, 4.05pm Venue: LT1414a (Seminar room, Livingstone Tower) Online: https://strath.zoom.us/j/82789104686?pwd=g1w5LFa4glTCFHzZbIKPX5qIBVEaKs.1 (Meeting ID 827 8910 4686, passcode whiteboard) What: MSP101 Planning meeting --------------------------------------------------------- From fredrik.nordvall-forsberg at strath.ac.uk Fri Sep 19 16:36:36 2025 From: fredrik.nordvall-forsberg at strath.ac.uk (Fredrik Nordvall Forsberg) Date: Fri, 19 Sep 2025 16:36:36 +0100 Subject: [msp-interest] [MSP101] Conor Mc Bride: Leftovers, Rightunders: Typechecking Thinnings Compositionally (1pm Mon 22/9, LT1310) Message-ID: <0beed8d4-17ba-49be-aa42-9fa33a421b39@strath.ac.uk> Comrades, We kick off a new semester of the MSP101 seminar with a talk by Conor. The regular time for the coming semester is Mondays at 1pm. Hope to see you there! Cheers, Fred Date, time and place: ? Monday 22 September, 13:00, Livingstone Tower room LT1310 Speaker: ? Conor Mc Bride (MSP) Title: ? Leftovers, Rightunders: Typechecking Thinnings Compositionally Abstract: ? In the interests of sharing MSP lore, I came up with a way to talk about both ? the "Input Subject Output" approach to typechecking and the Category of ? Thinnings in the same talk, making the latter an interesting example of the ? former. ? The Input Subject Output approach, like most bidirectional approaches to problem ? decomposition, tracks whether signals go from parent to child or vice versa, ? but it also acknowledges a signal has a guarantor as well as a sender, ? responsible for the meaningfulness of the signal. Meanwhile, thinnings are ? order-preserving embeddings between ordered sequences, or dually, selections ? of elements from sequences (their resemblance to binomial coffecients is no ? accident), and are thus a fine example of a monoidal category. ? I won't assume that any of you know know any of this: many of us do; more of ? us should. And I'll try to tell the story with pictures, drawn on a whiteboard, ? rather than jargon. ? I often use thinnings to talk about embeddings between scopes, the latter seen ? as sequences which grow on the right (because of prejudices about time). A ? compositional way to typecheck a thinning is to start with the available stuff ? "over" the thinning, together with a thinning that will start choosing from ? the newest stuff on the right. If all is well, we shall learn which "leftovers" ? have not yet been considered, and which "rightunders" have been not only ? considered but also selected. There is a healthy story about both the ? monoidal/parallel/spatial/tensor structure of thinnings and their ? categorical/sequential/temporal/composition structure, yielding an algorithm ? which never has to guess where to chop sequences in two. MSP101 Feeds: ? Web: http://msp.cis.strath.ac.uk/msp101.html ? RSS: http://msp.cis.strath.ac.uk/msp101.rss ? iCal: http://msp.cis.strath.ac.uk/msp101.ics From fredrik.nordvall-forsberg at strath.ac.uk Fri Sep 19 16:42:55 2025 From: fredrik.nordvall-forsberg at strath.ac.uk (Fredrik Nordvall Forsberg) Date: Fri, 19 Sep 2025 16:42:55 +0100 Subject: [msp-interest] Re: [MSP101] Conor Mc Bride: Leftovers, Rightunders: Typechecking Thinnings Compositionally (1pm Mon 22/9, LT1310) In-Reply-To: <0beed8d4-17ba-49be-aa42-9fa33a421b39@strath.ac.uk> References: <0beed8d4-17ba-49be-aa42-9fa33a421b39@strath.ac.uk> Message-ID: Clearly I don't remember how to do these announcements any more, as I forgot to include the Zoom link for online participation. Here it is: Zoom link: https://strath.zoom.us/j/82789104686?pwd=g1w5LFa4glTCFHzZbIKPX5qIBVEaKs.1 ?? (Meeting ID 827 8910 4686, passcode whiteboard) Don't worry, Fiona will take over more competently from next week onwards. Cheers, Fred On 19/09/2025 16:36, Fredrik Nordvall Forsberg wrote: > Comrades, > > We kick off a new semester of the MSP101 seminar with a talk by Conor. > The regular time for the coming semester is Mondays at 1pm. > > Hope to see you there! > > Cheers, > Fred > > > Date, time and place: > ? Monday 22 September, 13:00, Livingstone Tower room LT1310 > > Speaker: > ? Conor Mc Bride (MSP) > > Title: > ? Leftovers, Rightunders: Typechecking Thinnings Compositionally > > Abstract: > ? In the interests of sharing MSP lore, I came up with a way to talk > about both the "Input Subject Output" approach to typechecking and the Category of > ? Thinnings in the same talk, making the latter an interesting example of the former. > > ? The Input Subject Output approach, like most bidirectional approaches > to problem decomposition, tracks whether signals go from parent to child or vice > versa, but it also acknowledges a signal has a guarantor as well as a sender, > ? responsible for the meaningfulness of the signal. Meanwhile, thinnings are > ? order-preserving embeddings between ordered sequences, or dually, selections > ? of elements from sequences (their resemblance to binomial coffecients > is no accident), and are thus a fine example of a monoidal category. > > ? I won't assume that any of you know know any of this: many of us do; > more of us should. And I'll try to tell the story with pictures, drawn on a > whiteboard, rather than jargon. > > ? I often use thinnings to talk about embeddings between scopes, the > latter seen as sequences which grow on the right (because of prejudices about > time). A compositional way to typecheck a thinning is to start with the > available stuff "over" the thinning, together with a thinning that will start > choosing from the newest stuff on the right. If all is well, we shall learn which > "leftovers" have not yet been considered, and which "rightunders" have been not only > ? considered but also selected. There is a healthy story about both the > ? monoidal/parallel/spatial/tensor structure of thinnings and their > ? categorical/sequential/temporal/composition structure, yielding an > algorithm which never has to guess where to chop sequences in two. > > MSP101 Feeds: > ? Web: http://msp.cis.strath.ac.uk/msp101.html > ? RSS: http://msp.cis.strath.ac.uk/msp101.rss > ? iCal: http://msp.cis.strath.ac.uk/msp101.ics > > > > _______________________________________________ > msp-interest mailing list > msp-interest at lists.strath.ac.uk > http://lists.strath.ac.uk/mailman/listinfo/msp-interest