ε   ( resp .   η ) = { +  if pattern  V   ( resp .  W )  is over-represented    −  if pattern  V   ( resp .  W )  is unter-represented       .       ( 31  )    MathType@MTEF@5@5@+=feaafiart1ev1aaatCvAUfKttLearuWrP9MDH5MBPbIqV92AaeXatLxBI9gBaebbnrfifHhDYfgasaacH8akY=wiFfYdH8Gipec8Eeeu0xXdbba9frFj0=OqFfea0dXdd9vqai=hGuQ8kuc9pgc9s8qqaq=dirpe0xb9q8qiLsFr0=vr0=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@AC70@