### Question about von Neumann Algebras

#### Posted by Urs Schreiber

Jim Stasheff asks me to share this quote:

Study is hard work. It is so much easier to find something else to do in its place than to stay at the grind of it. We have excuses aplenty for avoiding the dull, hard, daily attempt to learn. There is always something so much more important to do than reading. There is always some excuse for not stretching our souls with new ideas and insights now or yet or ever.

by Joan Chittister

Quoted in Essential Monastic Wisdom, by Hugh Feiss .

And another email I receive reminds me of the truth of this. Somebody writes

In one of your entries in the $n$-category Café blog, you raised a question that is very relevant to what I’m doing. Did you settle the question in the end as to whether

allbimodules over von Neumann algebras really do for sure come from homomorphisms? Do you have any suggestions for what I can read to find out?

This reminds me of my feeble attempts to learn von Neumann algebra theory (was it here?), and how I already start forgetting what I did learn. I think the above statement, that all bimodules in fact come from algebra homomorphisms, is at least true for type III factors.

Somebody please help. Me, and, probably more importantly, the person who wrote the above message.

Posted at August 30, 2007 6:38 PM UTC
## Re: Question about von Neumann Algebras

Study is hard work, but how hard? I’ve been idly wondering for a while now how much energy it takes to think. Say we compare people watching for an hour at a corner cafe to thinking really really hard for an hour. Sometimes after this kind of thinking I’m really exhausted. So what’s the difference in calorie use?