Centre for Interdisciplinary Research in Computational Algebra (CIRCA) seminar

Adam Barwell will present Through Misfortune or Carelessness: Reassuring Reliability Through Repetition

Abstract: Computers that communicate with each other are now commonplace. However, the seemingly simple act of communication can be fraught with error with messages being lost, delayed, or corrupted. Protocols, e.g. TCP, specify what messages look like, what should be sent, and when messages should be sent. Protocols underpin the Internet, but are often written in plain English, and can contain errors, despite the aid of ASCII art diagrams. Conversely, session types are a formal approach for defining protocols, with correct-by-construction guarantees of desirable behavioural properties, e.g. deadlock-freedom. However, most session types assume that no failures can occur in the system. We aim to extend session types to enable definition of automatic repeat request (ARQ) protocols, which can provide key reliability assumptions for application-level programs. In this talk, we present a work-in-progress protocol description language for ARQ protocols whilst maintaining correct-by-construction guarantees in spite of the possibility that messages may be lost or delayed.This is joint work with Stephen McQuistin.

Vishesh Lonial will present Connectivity of product replacement graphs

Abstract: The Product replacement graph of a group has generating tuples as the set of vertices and the edges are constructed depending on whether we can reach from one tuple to another through the Nielsen moves. I will be providing a history of the work done in the field and giving a view of my work.

Further details about this event, along with information about CIRCA, can be found on the CIRCA website https://circa.st-andrews.ac.uk