The wiki article implies the Professor was fine with it, so stolen is maybe not correct.
" Harvard officials were not pleased that Gates and Allen (who was not a student) had used the PDP-10 to develop a commercial product, but determined that the computer itself, which technically belonged to the military, was not covered by any Harvard policy; the PDP-10 was controlled by Professor Thomas Cheatham, who felt that students could use the machine for personal use. Harvard placed restrictions on the computer's use, and Gates and Allen had to use a commercial time share computer in Boston to finalize the software."
