Interviewer: Would you like to write letters to other mathematicians?
Pierre Deligne: Writing a paper takes a lot of time. Writing it is very useful, to have everything put together in a correct way, and one learns a lot doing so, but it’s also somewhat painful. So in the beginning of forming ideas, I find it very convenient to write a letter. I send it, but often it is really a letter to myself. Because I don’t have to dwell on things the recipient knows about, some shortcuts will be all right. Sometimes the letter, or a copy of it, will stay in a drawer for some years, but it preserves ideas and when I eventually write a paper, it serves as a blueprint.
What type of letter is he talking about and why does he write a letter to other mathematicians?
I mean, there are many different types of letters out there. I mean, some love letters, friends letters, etc.