1st Semester 2024/25: Introduction to Topology in and via Logic

Instructors

Qian Chen, Rodrigo N. Almeida, Nick Bezhanishvili (Responsible)

ECTS

6

Description

Topology is one of the basic areas of contemporary mathematics, and finds applications in all areas of logic: from traditionally mathematical subjects (model theory, set theory, category theory and algebraic logic) to areas of philosophy (epistemic logic, formal epistemology), formal semantics or computation (domain theory, learning theory). Its key idea is that one can understand space through very simple units -- so called ``open" and ``closed" sets, and their interaction -- in a way that can capture both the intuitive properties of physical space, and also more abstract notions of ``space": spaces of ideas, information spaces, or even spaces of actions, for example, in computation.

In this project we will familiarise students with the basic concepts of topology as they are used in logical practice. This will consist in a series of introductory lecture recordings covering the basic core concepts one tends to encounter in these settings (continuity, neighbourhood filters, compactness, connectedness, separation); Q\&A sessions, guiding students through practical applications of the concepts, as well as guiding them in finding an appropriate presentation topic; as well as forays into more advanced topics, pursued by the students. Importantly, we will emphasise how topology appears naturally in many logical contexts.

Organisation

Students are encouraged to follow the recording, read the lecture notes and finish the corresponding assignments every week. There will be a Q&A session every week. The (tentative) schedule is as follows:

Week 1: A short online kick-off meeting + 3 lecture recordings (Continuity, Neighbourhoods and Separation axioms) + Q&A

Week 2: 3 lecture recordings (Separation Axioms, Compactness, Basic topological constructions and Connectedness) + Q&A

Week 3: Group consultations + Q&A

Week 4: Group presentations.

The topics of presentation will be suggested to students, and should focus on a more advanced concept or idea relating topology to logic. These can include (but are not limited to) specific aspects of the following broad topics: basic point-free topology; Polish spaces and the spaces of Cantor and Baire; Baire category theorems; Alexandroff and Boolean spaces; density and scatteredness. Students can also propose topics, so long as they fit in the scope of the project.

Prerequisites

Basic mathematical maturity as can be expected from having taken a course heavily reliant on proofs, e.g. Philosophical Logic, Dynamic Epistemic Logic or Introduction to Modal Logic. Attendance of these courses can be useful to appreciate some of the examples, but is not necessary.
Basic familiarity with topics of mathematical logic will be useful in choosing topics.

Assessment

Homework Assignments, Oral Presentation (week 4).

References

Ryszard Engelking, (1968) General Topology

Lecture notes with supporting material for the lectures.

More specific references will be made available during the project.