What is the name of this structure (describes relation: exp(log(a) + log(b)) = a * b)?

90 Views Asked by At

I recall reading some time ago about some pattern/structure in category theory. Now I need to study some related properties and can't recall the proper name of it.

Let me describe it (pardon me if I am not 100% precise with my notation).

Let A be monoid over set a, with identity element a_id and binary assoc. operation:

(a op_a a) -> a

Likewise B is a monoid over set b, with identity element b_id and binary assoc. operation:

(b op_b b) -> a

What is the name of structure S, that consists of:

  • A
  • B
  • mapping m1: a -> b
  • mapping m2: b -> a

... such that:

(a1 op_a a2) = m2(m1(a1) op_b m2(a1))

... for all a1, a2 in a?

Example of this in math is:

exp(log(a1) + log(a2)) = a1 * a2

... with A and B being monoids over rational numbers with multiplication and addition operations, m1 being log and m2 being exp.

Another S-like structure example is when you define mappings for integers <-> strings (where strings are limited to be repetition of some symbol n times) and sum and concat forming monoids.

So, what is the proper name for this structure in category theory (or other branches of math)?

1

There are 1 best solutions below

0
On BEST ANSWER

I was looking for group isomorphism. Kudos to commenters for pointing me in right direction.