All talks are both in-person and over Zoom, at 1pm, on Fridays; here is a view of the public ICS file:
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Friday Week 5 (Feb 9): Emily Barnard, Department of Mathematical Sciences in the Loop CDM 228 or over Zoom (join the mailing list and consult the archives for the Zoom link)
Title: pop-stack sorting and pattern-avoiding permutations
Abstract: The pop-stack sorting method takes an ordered list or permutation and reverses each descending run without changing their relative positions. In this talk we will review recent combinatorial results on the pop-stack sorting method, and we will extend the pop-stack sorting method to certain pattern avoiding permutations, called c-sortable. This talk will be accessible to all.
Friday Week 3 (Jan 26): Umer Huzaifa, SoC in Lincoln Park Campus
Title: Walking Strategies of Humanoid Robots, with applications to assistive devices
Abstract: Human movement is characterized by precise coordination of multiple joints and muscles, resulting in complex overall body dynamics. In my presentation, I will outline a methodology I developed to enhance the walking strategies of humanoid robots, making them more stylistic and human-like. Next I will present my extension of this work into human assistive devices and recent results in this regard. My research also delves into the realm of soft robotics. This field presents unique challenges, as the modeling of soft robotic systems does not follow the straightforward principles applicable to rigid robots. In one of our recent studies, we approached this challenge by conceptualizing the soft robot as a collection of interconnected rigid bodies, applying traditional modeling techniques. Finally, I will touch upon my latest foray into biomedical engineering. Here, my focus is on identifying biomarkers that can be used to monitor the health of active-duty personnel. This work represents a significant step towards enhancing health monitoring in demanding environments.
Friday Week 5, Oct 6: Salman Parsa, SoC in Lincoln Park Campus
Title: Reeb Spaces and the Borsuk–Ulam Theorem
Abstract: I will talk about Reeb spaces and their discretization called mapper. These are applied tools in topological data analysis. After showing a few examples, I will use the Reeb space to prove a partial extension of the well-known Borsuk-Ulam theorem for maps from \(2\)-sphere into \(\mathbb{R}\). This extension says that there are always two antipodal points \(S^2 \ni x, -x\) such that \(f(x) = f(-x)\) and the two points are connected in the preimage. The proof uses the concept of the Reeb graph which is a 1-dimensional Reeb space. I also consider the relationship between excess homology of the Reeb space of \(f: S^n \to \mathbb{R}^{n - 1}\) and the existence of the analogous extensions of the Borsuk–Ulam theorem for maps into \(\mathbb{R}^m, n > 2\).
Friday Week 9, Nov 3: Stefan Mitsch, SoC in Lincoln Park Campus
Title: The cyber-physical systems proof workhorse: quantifier elimination in the first-order theory of real closed fields
Abstract: Cyber-physical systems are characterized by interaction between discrete computational processes and their effects in continuous differential equation models of physics, biology, chemistry, etc. In proving universal and existential properties about such systems, many questions of interest reduce to questions in first-order real arithmetic. Conveniently, the first-order theory of real closed fields is decidable due to a seminal result of Alfred Tarski. Algorithms for quantifier elimination, however, are highly non-trivial and not proof-producing, which makes it difficult to construct an unbroken chain of proof arguments. This talk presents a formalization of quadratic virtual term substitution, a quantifier elimination procedure that is complete for low-degree polynomials.