Is divorce valid without the wife’s knowledge?

Question : It is permissible for a man to divorce his wife even if she does not know. For example, he may say, “My wife is divorced,” and appoint two witnesses, or he may say, “My wife is divorced,” without appointing witnesses, or he may write it in his own handwriting, whether she knows or not. Why?

Answer : It is required that… because her consent is not a condition. If her consent is not a condition, then there is no benefit, or rather no necessity, in her knowing about it.