Question

Give a recursive definition of the set of positive integers that are multiples of 4.


4∈S, and x+y∈S if x,y∈S.
4∈S, and x+8∈S if x∈S.
4∈S, and xy∈S if x,y∈S.
4∈S, and 4x+4∈S if x∈S.
4∈S, and 4x∈S if x∈S.

Answer 1

@jim_thompson5910 do you have any knowledge on how to do these\