# Kyoto University Applied Mathematics Seminar (KUAMS)

In the Department of Mathematics at Graduate School of Science, Kyoto University, we hold a seminar once in a month, inviting a broad spectrum of lecturers working in various fields of mathematics and fields that connect or are expected to connect in the future to applications of mathematics. We prepare a wide range of inspiring topics carrying the features of applied mathematics and we gladly welcome the participation not only of mathematicians but also of those who do research in fields related to mathematics and feel interested.

## Upcoming seminars

No. 61: June 25, 2019 (Tue) 16:30-18:00

Dr. Eiko Kin (Osaka University)

"Braids and entropies from taffy pulling machines"

**Abstract: **Taffy pullers are devices for pulling candy.
One can build braids from the motion of rods for taffy pullers.
According to the article ``A mathematical history of taffy pullers" by Jean-Luc Thiffeault,
all taffy pullers (except the first one) give rise to pseudo-Anosov braids.
This means that the devices mix candies effectively.
Braids are classified in three categories, periodic, reducible and pseudo-Anosov.
The last category is the most important one for the study of dynamical systems.
Each pseudo-Anosov braid determines its stretch fact and the logarithm of stretch factor is called the entropy.
Following a study of Thiffeault, I discuss which pseudo-Anosov braids are realized by taffy pullers, and how to compute their entropies.
I explain an interesting connection between braids coming from taffy pullers and hyperbolic links.
Interestingly, the two most common taffy pullers give rise to the complements of the the minimally twisted 4-chain link and 5-chain link which are important examples for the study of cusped hyperbolic 3-manifolds with small volumes.
If time permits, I will explain a construction of pseudo-Anosov braids.

**Note**: This talk will be given in Japanese.

No. 62: July 30, 2019 (Tue) 16:30-18:00

Dr. Hiroshi Takeuchi (Chubu University)

"TBA"

**Abstract: **TBA