That’s Mathematics Hall straight ahead, and Havermeyer Hall to the right. If I remember correctly, Mathematics and Philosophy were the two buildings named after individual departments of study. Several buildings, such as Law, Engineering, and Business, house separate schools within the university but I consider that a distinguishable from buildings named after fields that cut across multiple schools.
Havermeyer, while not named after a department is most famous for housing Columbia’s chemistry department, and for its grand lecture hall Room 309, which has been featured in numerous movies.
Although I did not study math while at Columbia, I spent a fair amount of time in Mathematics Hall during my undergraduate years, as I worked in the administrative offices where I mostly sorted mail.