computably

If mathbf A is the category of sets, then 𝛱_Bf is (up to isomorphism) the usual Cartesian product of the fibres A_y. If mathbf A is a category of spaces and smooth maps, then an element of 𝛱_Bf will have values varying smoothly in the indices, while if mathbf A models data types and computable functions the values will vary computably.