Recently I had a PhD interview for a very good university in Europe. The application was for the School of Mathematics, as I posses a Bachelor's and Master's degree in Pure Mathematics.
During the inteview I was quite nervous as it was a new experience for me and the questions posed were only of technical flavour. Questions about my thesis and a project that I concluded during my studies were asked. I was unable to answer most of the questions, as a lot of time had passed since I did my project and thesis, almost 6 months for the last one. After the interview though, as I calmed down, I realized that the answers to the questions were very easy to produce, though the questions were not at all trivial.
I should mention that a potential advisor commented on my thesis, saying that it was the first time he saw a master student write a thesis covering so much material and with such depth. Moreover, in my thesis I speculate about a potential connection between two theories. A thought that turned out to have some merit as some time later a publication appeared describing somewhat the same connection, (not by me).
Taking the above into consideration, I would like to ask wether the fact that I did not answer to the posed questions could be detrimental for my application. That is, if someone experienced a similar situation.
In case of rejection I would consider applying for US universities, though I will have to wait for a year. Do you think this will have a negative impact on such applications?