24 June 2020
- Title: A Mathematical Model for the Transmission of COVID-19 in Sudan
- Speaker: Abdelnasir Bongo
- Affiliation: University of Khartoum
The currently circulating Coronavirus disease 2019 (COVID-19) has reached Sudan by the mid of March 2020 or earlier. From the onset of the virus arrival, the government of Sudan has allocated isolation units across the country and gradually placed a series of measurements to prevent the disease from widespread community transition. In this talk, we will present a mathematical model for the transmission of COVID-19 in Sudan, using a modified version of SEI framework. We placed emphasis on quantifying the impact of the control measurements and the rate of case detecting in slowing down the spread of the disease. We will discuss the model results and consider other simulating scenarios.
17 June 2020
- Title: Projective fibrations through bigraded rings in low dimension.
- Speaker: Geoffrey Mboya
- Affiliation: University of Oxford
Scrolls play a central role in construction of varieties such as K3 surfaces and Fano 3-folds. I will define scrolls in a general toric set-up and describe line bundles on them with accessible examples. Using this background, I will introduce a set-up of probing the geometry of certain projective fibrations polarized by a pair of divisors, one ample and one relatively ample, which together embed the fibration into a “relative key variety” over a base.
Finally, I will give an informal insight on why one would care about this kind of mathematics.
10 June 2020
- Title: Further investigations on a permutation code introduced by Mantaci and Rakotondrajao.
- Speaker: Fufa Beyene
- Affiliation: Addis Ababa University
Permutation codes are interesting because certain algorithms perform better over the codes (vectors) than they do over the permutations themselves. Codes allow for instance to implement efficient algorithms for the exhaustive generation of all permutations or of some given classes of them. To do so, one has often to “read” the properties of the permutation in its code and this gives birth to interesting combinatorial problems.
In 2001, R. Mantaci and F. Rakotondrajao introduced a new code (M-R code) for permutations and in this talk we present some investigations we have conducted over this code and results we have found.
See a detailed abstract here
3 June 2020
- Title: Quantifying Traffic Congestion in Nairobi: A Topological Approach
- Speaker: Eric Bojs
- Affiliation: KTH Royal Institute of Technology in Stockholm, Sweden
African cities are growing. In conjunction with economic prosperity, cities are experiencing what seems to be a never-ending traffic problem. This project aims to give insight into a novel approach for quantifying car traffic in those cities. This is necessary to improve efficiency in resource allocation when trying to fix traffic.
In the form of a case study in Nairobi, the approach consists of a method which relies on topics from the field of Topological Data Analysis, together with the use of large data sources from taxi services in the city. With this, both qualitative and quantitative insight can be given about the traffic. The method was proven useful for understanding how traffic spreads, and to differentiate between levels of congestion: quantifying it.
27 May 2020
- Title: Low-dimensional Hom-Lie algebras
- Speaker: Elvice Ongong’a
- Affiliation: University of Nairobi and Mälardalen University, Sweden
Hom-Lie algebras are considered to be generalization of Lie algebras by having an additional linear map, the twisting map. This gives a generalization of the Jacobi identity into Hom-Jacobi identity. In this talk, we give some preliminaries on Hom-Lie algeras of low dimension and describe isomorphisms of such algebras. We further describe the dimension of the space of possible linear endomorphisms (twists) that turn skew-symmetric low-dimensional algebras into Hom-Lie algebras.