Definition 5.62.

Let \(\varphi\colon T \to S\) be a morphism of logoi.

  1. We call \(\varphi\) a monogenic quotient if it is a quotient map (Definition 4.19) whose kernel is a monogenic congruence.

  2. We call \(\varphi\) an epigenic quotient if it is a quotient map whose kernel is an epigenic congruence.

  3. We call \(\varphi\) conservative if it only inverts isomorphisms.

  4. We call \(\varphi\) weakly conservative if it only inverts effective epimorphisms.