## Validity of Working with Naked Tuples progressively

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### Validity of Working with Naked Tuples progressively

I'm looking to solve last Saturday's (28/04/2017) Sudoku puzzle from the UK's Guardian newspaper. I can make progress if I indulge in using progressive "Naked Tuples", but this progression involves swapping dimensions. I'd like to confirm that the dimension swap is valid and logical.

Here is a picture of the puzzle. The red ovals match 1,6 Tuples from the central sub grid and allows the elimination of 6 from the available contenders 4,6,9 in cell (5,6). This leaves a new naked tuple of 4,9 in cells (5,6) and (6,6) - marked in orange. This allows the elimination of these values from cell (9,6), giving cell result of 6. Does this make sense?

SuDoku_GUA20170429_FullDataGrid.PNG (20.45 KiB) Viewed 245 times
swaatacba

Posts: 16
Joined: 09 February 2017

### Re: Validity of Working with Naked Tuples progressively

Your eliminations are valid, but depending on what you mean by "dimension swap", the logic may or may not be exactly what you think it is.

The Naked Pair of 1 and 6 in R4C4 and R4C5 is a naked pair in both row 4 and in box 5. Thus it causes eliminations in both contexts. It isn't that you have found a naked pair in on dimension and can make eliminations in another dimension. It is more like you found a naked pair that can be viewed in two different ways, and you get to use both interpretations to make eliminations.

In a similar way, the subsequent naked pair of 4 and 9 in R5C6 and R6C6 can be viewed as happening in block 5 and in column 6. The column 6 view has an elimination in this case.

JasonLion
2017 Supporter

Posts: 640
Joined: 25 October 2007
Location: Silver Spring, MD, USA

### Re: Validity of Working with Naked Tuples progressively

Thank you, Jason.
swaatacba

Posts: 16
Joined: 09 February 2017