Respected researchers giving imprecise or misleading explanations in casual conversations I have attended quite a few large conferences in mathematics where experts from different fields participate. Naturally I talked to some people and asked them a very basic question: what they are working on. In some cases the answers were not very precise and even rather misleading. I had the feeling that these people tried to make an impression that they work in one field while they work in another one.

One of the worst examples of such discussions was as follows. The person said that he works in interplay of random series and quantum fields. I never heard that there is a connection between the two subjects and asked to elaborate.  His explanations were chaotic: he started to explain on random series without any mention of quantum fields. I asked again how it is related to the latter. He said something about quantum field without mention of random series. After a couple more questions he continued to jump between the two subjects without explaining the relation. The funny thing is that after this discussion I found his list of publications and realized that all his publications belong to a third area which has apparently nothing to do with the two above topics. To my greater surprise, this person is actually a respected mathematician from a good math department. 


  My impression is that the situations as above are not exceptional. Am I wrong? How typical they are? Is there any rational explanation of such a behavior?


My question might be non-appropriate for this site, sorry about that.   Personally I find the situations I have been in quite strange, and I would like to have any comment if it is something typical in academia (at least in mathematics) or not.
There is nothing strange about this. Not everyone is good at translating the very technical problems they are working on, without advance preparation, on demand and at a moment’s notice, into a polished speech that a random person they encounter (mathematician or not) will find understandable. I think the correlation between what you observed and the quality of this person’s work is essentially zero.

As for the fact that you found his description “misleading” because his papers suggest he usually works on other topics: well, he may be trying to do new work in an area he hasn’t worked on before. This is often my situation, and my own answer when people ask me what I’m working on (especially if the question is posed in the present tense as in your description) will occasionally have little or nothing to do with anything I’ve published.