[ 201 ] update book

msp201.md

@@ -14,13 +14,13 @@ Everyone is welcome to join and inquire about the current location and time of t
 
 ### Current study group
 
-Since January 2023, we are reading the following book:
-
-- *Introduction to Homotopy Type Theory*, E. Rijke [[link]](https://arxiv.org/abs/2212.11082).
+Since January 2024, we are reading the following book:
 
+- *Sheaves in Geometry and Logic*,  S. MacLane, I. Moerdijk.
 
 ### List of previous 201s
 
+- Spring 2023: *Introduction to Homotopy Type Theory*, E. Rijke [[link]](https://arxiv.org/abs/2212.11082).
 - Fall 2021: *Initial Algebras, Terminal Coalgebras, and the Theory of Fixed Points of Functors*, J. Adámek, S. Milius and L. Moss.
 - Spring 2021: *Categorical Systems Theory*, D. J. Meyers [[link]](http://davidjaz.com/Papers/DynamicalBook.pdf).
 - Fall 2020: *Algebraic Theories: A Categorical Introduction to General Algebra*, J. Adámek, J. Rosický and E. M. Vitale [[link]](https://perso.uclouvain.be/enrico.vitale/gab_CUP2.pdf).