•Time t and space p vary from 0 to nk-1
–Represent them as k-tuples
•Can define t < t’
[ how ? ]
•Can define succ(t, t’)
[ how ?]
•Goal: express the following:
T0(p, t) =
true iff tape has 0 on p at time t
T1(p, t) = true iff tape has 1 on p at time t
Hq(p, t) =
true iff head is on p at time t, state q
•All these can be expressed by simultaneous fixpoint [ how ?
]