Constructing Equalizers in Type Theory

In the presence of Ξ£-types, one may construct all equalizers. Given types 𝐴 and 𝐡 with functions 𝑓,𝑔:𝐴→𝐡, the equalizer may be constructed as

π–Ύπ—Šπ‘“,π‘”β‰”βˆ‘π‘Ž:𝐴(𝑓(π‘Ž)=𝑔(π‘Ž))
equalizers-in-type-theory note entries/category/equalizers-in-type-theory.hel