PG and AGE math functions ambiguity

[Hunaid2000]

Hi everyone.
I noticed that most of math functions are already defined by Postgres (https://www.postgresql.org/docs/8.3/functions-math.html). So my question is why are these functions defined again by AGE?
E.g. atan2 in PG and age_atan2 in AGE.

[jrgemignani]

A lot of PG functions can't be used directly due to differences between the Cypher specification and PG. This means that we either make our own functions or wrap PG functions or both.

In order to eliminate the ambiguities (due to naming and compilation) between Cypher and PG names, we distinguish our functions with a prefix of age_

That is why there are two. If you look at the code, you'll see this as well.