Redraws redux

For no particular reason, I've been thinking about redraws in hold'em a bit lately. Here's another illustrative example:

Consider two holdings:

• 5♣5♥ (chosen in honour of guess who)
• 6♣7♣

on a board of 5♦8♦9♥. In both cases your opponent holds A♦K♦.

The set, with its redraws to a boat, has a 75/25 edge, whereas the flopped straight, which is dead if the diamond flush hits, has only a 63/37 edge.

In practical terms, the A♦K♦ hand would be correct to call a pot sized all in bet if he felt that he was up against the flopped straight, but not against the set.