Just thinking about some mathematical problems related to sigma models and string theory wandering round the new physics building in Warsaw…there are some nice views of the city from the 5th floor

View from the 5th floor

Pałac Kultury i Nauki

Then just around the corner I met this man…

However, much like Banach, he was not very talkative… my regular coffee guy is a much better conversationalist and knows a thing or two about sigma models.