[rules-dev] Expressivity in business rules.

Hello all, I am doing an study about differences between business rules and semantic web rules and came up with a doubt. While in semantic web there is a need in having decidable rules, frameworks such us Pellet works with rules considered DL-Safe that guarantees the decidability; business rules engines instead try to offer the more expressivity possible. Does it mean that business rules are not decidable? Why such difference? Thank you very much Javier Chamizo