1. The rank problem is decidable for finite groups and for finitely generated abelian groups.

2. Analogising is a decidable or an undecidable task so we can say it is a decidable task if we are not only thinking of assessments by tests and assessments that can summarized in a mark or percentage or rank

3. In 1929 and 1930, it was proved the truth or falsity of all statements formulated about the natural numbers plus one of addition and multiplication, was decidable, i.e. could be determined by some algorithm.

4. Based on a decidable notion of recursivity of procedures (or functions) in ALGOL-like programs we define pseudo-recursive procedures to be those that do not need an activation record of their own on the runtime stack; their storage can be allocated within the activation record of a strictly-recursive (i.e. not pseudo-recursive) dynamic predecessor.