Monday evening Lisa Randall gave a public talk on extra dimensions. She was tired but the talk was good. Even though it was announced as a public lecture it was really addressed only to the participants. After Lisa's talk there was an opening ceremony for the conference. Representatives of the main Brazilian sponsors of the conference were there and possibly that is the reason the opening was not in the morning as it should be. In Brazil formal aspects are more important than its contents.

Yesterday (Tuesday) there were three plenary lectures but only one with some interest to me. It was given by Bruce Kleiner and he talked about Perelman's work on Ricci flows and the geometrization conjecture. I was not aware that there are many papers explaining Perelman's work and that mathematicians like to write explaining other people works. The parallel session on string theory started with Sergei Gukov talking on categories and its application to link homologies and generalizations based on topological field theories. Hard stuff with the usual cartoons. Then Anton Kapustin gave a very clear talk on topological reduction of supersymmetric gauge theories. He explained in some detail the twisting procedure and how it can be used to get a topological or semi-topological field theories. The last string talk was given Marcos Marino on phase transitions in topological string theories. Again too mathematical.

Then I went to the parallel session on general relativity. The Brazilian GR community must be angry with its contents. The first talk was given by Gabriel Cardoso about entropy in supergravity and string theory where he proposes a modified OSV (Ooguri-Strominger-Vafa) relation to take into account subleading corrections to the entropy. The OSV proposal was discussed by Lubos. The second was a talk on loop quantum gravity. In fact, loop quantum cosmology, by Martin Bojowald, where the use of difference equations is claimed to allow the study of the singularity problems. Great if true. The last talk was given by Axel Kleinschmidt on the attempts to understand M theory looking at the symmetry structures hidden in D=11 supergravity. It is nice to see that there are signs of integrability there too.

I didn't see the end of the last talk because I had to catch my flight back to Sao Paulo. I went to Rio just for the string theory sessions. After I left, the Poincare Award ceremony took place. It was awarded to Ed Witten, Ludvig Faddeev and David Ruelle. All of them gave a talk on the Young Researchers Symposium held on Saturday and Monday.

The conference goes until Friday but I will not be there. Today there are only plenary talks and the afternoon is free. At night there is the conference dinner at Porcao, a very good barbecue restaurant in Rio. I will miss Zarembo's talk on Friday. Hope somebody can tell me later on.

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