1. DNA Solution of Hard Computational Problems
Richard J. Lipton
Science, Vol.268, pp , April 1995.

2. NP problems Adleman solved Hamiltonian path problem.
All NP problems can be efficiently reduced to HPP.
 We can solve all NP problems
 But, we need more efficient way, not brute-force method. (Only can solve 70 or less node HPP.)

3. The criterion of computing speed
How many parallel processes
Biocomputer: 3g of water  1022 molecules
How many steps each can perform per unit time
Supercomputer: 100 million op/sec
Biocomputer: limited to lab experiments.

4. Satisfaction problem (SAT)
The SAT problem is to find Boolean values for x and y that make the formula F true.

5. Solving SAT y x 1 1 a3 a2 a1 X’ Y’
Generating sequences similar with Adlman’s approach
Sequence length = 20bp

6. Solving SAT Generate sequence.
t1 = E(t0, 1, 1), t1’ = E(t0, 1, 0). Pour t1 and t2 to t3.
t4 = E(t3, 1, 0), t4’ = E(t3, 1, 1) t5 = E(t4’, 2, 0). Pour t4 and t5 to t6.
Check sequence in t6

7. Example Test tube Values present t0 00, 01, 10, 11 t1 10, 11 t’1

8. General case
Any SAT problem on n variables and m clauses can be solved with at most order m extract steps and one detect step.