Following much recent debate on Trial & Error vs Logic,

I would like to point out that, there is NOT a qualitative

difference between them:

You see, in logic, you try to eliminate all possibilities until

you reach the conclusion that only 1 number can go into

a particular square. Now, what you are actually doing is

trying out all other possibilities and eliminating them, until

you have 1 valid solution left. T&E does exactly the same

except perhaps more randomly and with longer sequences

in the elimination process. However, foundamentally, T&E

is the same as Logic, as approaches to Sudoku. Logic is,

in essence, a directed T&E.

Example: Fri Mar 19, Times T2, I solved it by logic, as usual,

but there was a step in the middle I had to postulate a

number and follow its implications for about 7-8 steps

before I could eliminate that scenario. That is T&E.

I am very interested in hearing how computer algorithms

cope with the problem of Sudoku. As far as I know, there

is no effective reduction schemes for this. Anyone?