A Case Study

SEU140+2

• If A ⊂ B and B ∩ C = ∅ then A ∩ C = ∅
• Data suggests looking at the proofs

Proofs

• EP elegantly uses ∈, ⊂, ∩=∅
• Metis and SInE use ∈, ⊂, ∩=∅, ∅, \, ∩
• VampireLT uses ∈, ⊂, ∩=∅, ∅, \, ∩, ∪
• Grzegorz Bancerek's proof similar to that of Metis and SInE
• EP finds a better proof?