- A
*relevance measure*measures relevance of a formula to a conjecture - Necessarily approximate (or P = NP)
- Adopt ideas from document retrieval research
- Variations galore

- The
*contextual intersection*Π between`Fa`and`Fc`in the context of the set`S`is|{f:f∈S,s∈sym(f)}| ∑ ( 1 - ------------------- ) s∈(sym(Fa)∩sym(Fb)) |S|

- The
*contextual direct relevance*between`Fa`and`Fc`in the context of the set`S`is|sym(Fa) Π sym(Fc)| -------------------- |sym(Fa) ∪ sym(Fc)|

- The "weakest link"
*path relevance*between`Fa`and`Fc`ismin direct-relevance(Fi-1,Fi) i=1..n ---------------------------------- n

- The
*transitive relevance*between`Fa`and`Fc`ismax path-relevance(Fa,Fc)