Other options for accommodation
One other option for accommodation is a room in one of the guesthouses on the campus of the University of Oslo. These rooms are in small guesthouses with shared kitchen and bathroom facilities, are very conveniently priced, but must be booked well in advance. Reservations must be made via the University of Oslo and are only possible on a Friday to Friday basis (e.g. June 8 to June 15) at a total price of 2000 NOK. To get from the guesthouse to the venue of the conference one can walk (about 40 minutes) or take a metro from Blindern to Nationaltheatret (2 stops), either of the lines 3, 4, 5 in the direction of city centre. If you are interested in this option you should contact Nadia Larsen at nadiasl@math.uio.no.
Another option for cheaper accommodation is at Haraldsheim Youth Hostel in Oslo. The standard at the hostel is good, and it is generally possible to book a single room.