Kernels, in a nutshell
Jeremy Gibbons · Journal of Logical and Algebraic Methods in Programming · 2015
A classical result in algebraic specification states that a total function defined on an initial algebra is a homomorphism if and only if the kernel of that function is a congruence. We expand on the discussion of that result from an earlier paper: extending it from total to partial functions, simplifying the proofs using relational calculus, and generalising the setting to regular categories.