An illustration of a magnifying glass. An illustration of a magnifying glass.

For more information about countable and uncountable sets, see books about "Analysis" (as advanced calculus is called). For example, Introductory Real Analysis, by A.N. Kolmogorov and S.V. Fomin (see ...

Why not use lambda's to make up a set's behaviour? If it's countable, then there should be a mapping from the ints to an element in the set and vice versa. A lambda can be passed in that checks ...

This is an implementation of the Z mathematical toolkit in Isabelle/HOL, as described in ISO 13568:2002. - Z_Toolkit/Countable_Set_Extra.thy at main · isabelle-utp/Z_Toolkit ...