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Almost Linked Set (ALS)
  An Almost Linked Set is one candidate (or tertiary unit) short of being a Naked and/or Hidden Subset. Basically, it is X number of cells that contain only X+1 number of candidates, or X number of candidates found in only X+1 number of cells. The extra candidate or tertiary unit is referred to as the fin, a term taken from a near-identical concept known as finned fish.

  The following logic holds true. If the fin is false, then the subset is true. In essence, the fin is weakly connected to the subset.
  Note also that if all of a candidate in an ALS are found in a single other unit, then you can consider potential eliminations of all others of that candidate in that separate unit. This concept is only noteworthy in ALS's, because in standard subsets it is swallowed up by the simpler techniques of pointing and claiming.

Elders of Genova
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