Model Theory Seminar | Jananan Arulseelan (Iowa State University)
	
 Nov 21, 2025 
 12:30PM to 1:30PM





	





























Date/Time

Date(s) - 21/11/2025
12:30 pm - 1:30 pm





Speaker: Jananan Arulseelan (Iowa State University)


Location: Hamilton Hall, Room 410


Title: Computability and Sherman’s S Factor


Abstract: In 2020, Ji, Natarajan, Vidick, Wright and Yuen announced their seminal MIP* = RE result, settling the Connes Embedding Problem in the negative. Shortly after that, Goldbring and Hart isolated the computable continuous logic content of the aforementioned result to show that the universal theory of the hyperfinite II_1 factor is not computable. This yields a vast strengthening of the negative solution to the CEP.




Very recently, Junqiao Lin announced that MIP^{co} = coRE, which serves as a dual result to MIP* = RE. We will explain this result and use it to show that the universal theory of any locally universal II_1 factor (for example, Sherman’s S factor) is uncomputable. In this setting, the corresponding embedding problem is true by definition. However, we still conclude interesting structural results about von Neumann algebras. Joint work with Aareyan Manzoor.