“…The proof assistant Agda/Alfa Agda [7] is the latest version of the ALF-family of proof systems for dependent type theory developed in Göteborg since 1990. Alfa [17] is a graphical interface for Agda. They assist users as structure editors for well-typed programs and correct proofs, by checking each step of the construction on the fly, by presenting possible next steps, by solving simple problems automatically, etc.…”