•Canonical Structure
•
•Any algorithmic computation
on A can be decomposed
•Compute the ¼k equivalence relation on k-tuples, and order the equivalence classes ) in LFP
[how do we choose k ???]
•Then compute on ordered structure ) any complexity
•
•Consequence: PTIME=PSPACE iff
IFP=PFP
•But note that DTC ¹ TC yet L ¹? NL [ why ?]