## DIC Chains

Advanced methods and approaches for solving Sudoku puzzles

### DIC Chains

I have been trying to location some information and examples of DIC chains. There seems to be a lot of information on DIC Chains but not
with actual examples. I used "Google" to reference these sites. I am
asking if any of you could supply me with a few reference sites that
include actual examples of DIC chains. Also, what are the differences
between DIC chains and Forcing Chains? Many thanks.
Gee

Posts: 50
Joined: 18 March 2007

### Re: DIC Chains

Gee wrote:I have been trying to location some information and examples of DIC chains. There seems to be a lot of information on DIC Chains but not with actual examples. I used "Google" to reference these sites. I am asking if any of you could supply me with a few reference sites that include actual examples of DIC chains. Also, what are the differences between DIC chains and Forcing Chains? Many thanks.

I can only conclude that your query to Google was flawed because there are (old) examples of DIC around.

There are (apparently) two different definitions for DIC. One of them is for a Double Implication Forcing Chain. That should answer part of your question.

Here's an example where alternate paths are followed from a bivalue cell.

Code: Select all
` [r1c8]=2                                      => [r1c3]=5 [r1c8]=4 [r1c5]<>4 [r9c5]=4 [r9c2]=5 [r2c2]=2 => [r1c3]=5 +--------------------------------------------------------------------------------+ |  3       1       25      |  6       4578    89      |  2789    24      789     | |  6       25      4       |  79      3578    389     |  23789   1       3789    | |  8       9       7       |  1       2       34      |  5       6       34      | |--------------------------+--------------------------+--------------------------| |  129     348     12369   |  79      13678   5       |  23678   24      13678   | |  1245    7       12356   |  238     1368    12368   |  2368    9       13468   | |  129     238     12369   |  4       13678   123689  |  23678   5       13678   | |--------------------------+--------------------------+--------------------------| |  24      6       8       |  23      9       234     |  1       7       5       | |  7       35      12359   |  25      16      126     |  4       8       69      | |  159     45      159     |  58      1468    7       |  69      3       2       | +--------------------------------------------------------------------------------+ # 121 eliminations remain`

This AIC is just as effective:

Code: Select all
` [r1c3]=5=[r1c5]=4=[r9c5]-4-[r9c2]-5-[r2c2]-2-[r1c3]-5`
daj95376
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Joined: 15 May 2006