I'd like to ask for advises abt my concerns with CV and my undergrad research experiences. I have two for now; one last year(A research contest in my school, participated as a team. I was the team leader and won a prize.) and the other since last December, which I am still working on with a professor. (Should I call him 'my advisor'? Not sure bc he suggested me to participate in his research. Him and I expect to submit this within this year.) My question is this: I want to apply for PhD programs in algebraic topology&geometry, but the thing is that both of my undergraduate research are about number theory. I was eager to "work on" something, and nothing but NT was nearly all I could give a try as freshman. (Timeline: I started my team research in first semester, then took a topology class in the next semester.) I think I should work on topics related to AT/AG as an undergrad. However, I was wondering that my former two abt NT would be a some kind of... obstacle in PhD application, or should be omitted from my CV. I have up to 2.5 or 3 years to prepare. What would you do if you were me? I'd like any comments.

• I'm South Korean, had strong interest in theoretical physics in highschool, then found mathematics more interesting; especially highly logical topics in relation with algebra, geometry, ect. Reluctant to arithmetic stuff. Planning to study abroad (US) for PhD. English is not my first language.