Information on how to get to Oxford by air, train or car can be found here.
For train or coach travel you may use the UK Railways site.
If you travel by car, here is a map of the UK with the main roads leading to Oxford, and here is a map of the Oxford Ringroad.
If you come by Eurostar, once you arrive in London St. Pancras, take the London Underground (metro), Circle line or Hammersmith and City line, to London Paddington. Here is a map of the London Underground. It is also worth checking here if the service is normal.
There is a direct train for Oxford leaving from London Paddington every hour (see the UK Railways site).
The conference takes place in Exeter College. You may see the college on this map of the city centre, it appears as number 8. You may also see Exeter college here.
On this detailed map of the centre of Oxford the streets are more clearly seen.
The talks are in the Saskatchewan Lecture Theatre. The Exeter College Lodge is on Turl street, when you enter you are in the Main Quad (see photo on the top of this page). You must go around the college chapel and enter the second Quad. The stairs going down on the right lead to the Saskatchewan Lecture Theatre. For a view of the two Quads of Exeter and of the location of the Saskatchewan Lecture Theatre, it suffices to zoom on this map.
On this map you may see the various departments of the University of Oxford (the Mathematical Institute appears as number 36), and here you may find a map with museums, libraries and places of interest.