This week we
welcome Alessandro Barp from Turing Institute to give a talk in our
OxCSML seminar entitled "What is a distribution? Constructing a
geometric backbone for statistical methodologies". The details are
below. Looking forward to seeing you there.
Saif & Hai-Dang.
Speaker: Alessandro Barp, Turing Institute
Time and date: 2pm-3pm, Friday 2 Feb
Place: Room LG03 (Small Lecture Theatre), Dept. of Statistics, Oxford
Title: What is a distribution? Constructing a geometric backbone for statistical methodologies
Abstract:
Many powerful methods in statistics and machine learning, such as
Hamiltonian/Langevin algorithms, flow matching, gradient descent,
reproducing kernel methods, and score-based discrepancies, are
inherently geometric. However, geometry remains notably absent from the
curriculum of most statistics departments, underscoring the perception
it isn’t an integral part of statistics. In this talk, we argue that
this misconception stems from the formalisation of distributions as
probability measures, which tends to isolate statistics from the rest of
mathematics. Instead, we propose employing the powerful intrinsic
geometry of smooth distributions as a mathematical backbone for
statistics, upon which generalisations (e.g., discrete or
non-commutative distributions) can be gradually constructed. In
particular, we characterise the differential information of
distributions used in score-based methods, explaining why it is not
given by the log-density gradient, but rather by Lie algebroids that
specify three differential operators, (i) the canonical Stein operator,
(ii) the curl, which describes measure-preserving systems; (iii) and a
covariant derivative that generate statistical discrepancies, providing a
unified perspective on log-density derivatives, score-matching, and
canonical Stein discrepancies. Remarkably, key abstract mathematical
ideas (e.g., the dualities between gradient-driven mechanics and
calculus, or between geometric spaces and function spaces) naturally
emerge as we merely reflect on the structure of distributions, which
helps us navigate the sporadic emergence of geometric tools across
applications.
Zoom:
https://zoom.us/j/99855897488?pwd=WnUxZVJ0ZHQ2UjVRK2xSVW9kN2xiZz09