How to answer this escapes me. Are there four adult males present when a woman commits adultry with a man. Do they post invitations?
Nope. The story is that Mohammed's favorite wife got lost during a night march in the company of a handsome young soldier. The next day, when she caught up with the rest of the group, some demanded that Mohammed have her executed to "cleanse his honor."
He didn't want to do this, so he had the convenient revelation that four male witnesses were required to prove adultery by a women, thus making it almost impossible to prove under the letter of the Koranic law. Of course, Muslims have found a lot of ways around this ruling, but that is what the Koran says.
It is fascinating that what the Koran actually says about women and adultery is almost exactly the opposite of what most Muslims actually do.