|{f:f∈SetF,s∈sym(f)}| ∑ ( 1 - --------------------- ) s ∈ sym(Fi)∩sym(Fj) |SetF|
ΠSetF(Fi,Fj)
-------------------
|sym(Fi) ∪ sym(Fj)|
min contextual-direct-relevance(Fi-1,Fi) i=1..n ------------------------------------------- n
max weakest-link-relevance(F0,Fn)