The term ``saturated,'' referring to a class of morphisms in a category, is used in the literature for two nonequivalent concepts. We make precise the relationship between these two concepts and show that the class of equivalences associated with any monad is saturated in both senses.
Keywords: saturation, orthogonality, monad, shape, category of fractions.
2000 MSC: 18A40.
Theory and Applications of Categories, Vol. 7, 2000, No. 4, pp 43-46.