Hi,
No, mathematics students are not eligible for UGC NET but they are eligible for CSIR NET exam. CSIR NET exam is for science stream students while UGC NET is for non-science stream students.
There are the following subjects for CSIR NET:
1. Chemical science
2. Earth Science
3. Life Science
4. Mathematical science
5. Physical Science
So as a mathematics student, you can apply for mathematical sciences subject for CSIR NET exam.