ronk wrote:champagne wrote:ronk wrote:champagne, are you pulling my chain, or do you really not know the definition of a native strong inference?

what is your definition of a native strong inference

A single native strong inference set is the set of candidates in one cell, or the set of like-valued candidates in one row, column or box. Judging from your earlier response, the "abi loop" using derived sis ...

you wrote:1r7c1 - 1r9c2 = 3r2c2 — 3r3c1 = 1r3c9 — 1r1c8 = 3r9c8 - 3r7c7 = 1r7c1

... becomes (continuing your notation style) ...

1r7c1 -

1r9c2 = (1-3)r4c2 = 3r2c2 — 3r3c1 = 1r3c9 —

1r1c8 = (1-3)r6c8 = 3r9c8 - 3r7c7 = 1r7c1

after replacing the (red) derived sis with (blue) native sis. Now this may look like just a longer version of the same thing, but it exposes

an embedded impossible loop ... (1-3)r4c2 = 3r2c2 — 3r3c1 = 1r3c9 — 1r1c8 = 1r6c8 ... within the

continuous loop that it appears to be. The

impossible loop is impossible because it contradicts the exocet assumption that produced it.

we are missing one or 2 more posts and I'll be completely lost.

1r7c1 - 1r9c2 = 3r2c2 - 3r3c1 = 1r3c9 - 1r1c8 = 3r9c8 - 3r7c7 = 1r7c1

this is, as far as I know, an Alternate Inference Chain written strictly following the rules in that forum.

For sure, each strong inference is depending on the initial assumption (13r5c46) but this is true for the 4 strong inferences, not only for 2 of them

If only native sis are authorised in an AIC, the garbage collectors will be filled of nearly all AIC's published in that forum.

No more basic group, no more ALS AHS groups ......

1r7c1 - 1r9c2 = (1-3)r4c2 = 3r2c2 - 3r3c1 = 1r3c9 - 1r1c8 = (1-3)r6c8 = 3r9c8 - 3r7c7 = 1r7c1

I don't know what is that animal, but for sure it's not an AIC. I am only using AIC's so I can't publish that, I just don't understand it.

To stay positive, As I am not aware of the writing rules for complex situations (if they do exist), I prefer to expose the situation step by step.

In that case

. effect of the assumption

. inferred (embedded) loop

. consequences of the inferred (embedded) loop

I have no objection to any rewriting of that logic.

I just say the logic is perfect (even without the exocet effect)