simplify_full() fails to simplify simple constant expressions to zero

[mezzarobba]

An issue found by Victor Spitzer: Sage fails to simplify

sage: f = log(sqrt(2) - 1) + log(sqrt(2) + 1)
sage: f.simplify_full()
log(sqrt(2) + 1) + log(sqrt(2) - 1)

without help. Doing

sage: f.simplify_real().simplify_log()
0

works, but it would be nice if simplify_{log,full}) detected by themselves that simplify_real() is applicable in this case.

Component: symbolics

Issue created by migration from https://trac.sagemath.org/ticket/23738

[mezzarobba]

Description changed:

--- 
+++ 
@@ -1,10 +1,14 @@
-In this example:
+An issue found by Victor Spitzer: Sage fails to simplify
 
 ```
 sage: f = log(sqrt(2) - 1) + log(sqrt(2) + 1)
 sage: f.simplify_full()
 log(sqrt(2) + 1) + log(sqrt(2) - 1)
+```
+without help. Doing
+
+```
 sage: f.simplify_real().simplify_log()
 0
 ```
-it would be nice if `simplify_{log,full})` detected by themselves that `simplify_real()` is applicable.
+works, but it would be nice if `simplify_{log,full})` detected by themselves that `simplify_real()` is applicable in this case.