Hello! I'm not sure if this is the right place to ask the question, but I'll be glad if someone answers to me.

I already prepared my application and payed $40 for TOEFL+GRE, but when checked at the Mathematics department at Yale, I didn't recognize almost any Number Theory experts there. In one of the recommendation letters my tutor has written that NT is my field of interest, so I have to know if it's worth it to pay $100 more for the application fee or not.

Thank you in advance!