Using this tiny data set 
key|source
 a | a
 a | c
 b | c
 b | b

[download]
gives a set containing 3 sources [a,b,c].
Shouldn't the result show some reduction, either 2 [a,b] or 1 (the minimum)[c] ?
poj

In reply to Re^2: Contemplating some set comparison tasks by poj
in thread Contemplating some set comparison tasks by dwhite20899

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