> That's the irrefutability of the law of the excluded middle, and yes it's > probably the most difficult of the regular exercises. Here you go >
BTW, if someone is still trying to solve it himself there is a hint in previous tasks. Look at De Morgan's law which convert disjunction into conjunction - it contains all the necessary steps. That's exactly how I was able to solve it. -- You received this message because you are subscribed to the Google Groups "Metamath" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To view this discussion on the web visit https://groups.google.com/d/msgid/metamath/32ea2c40-a772-480f-9f4f-dfd77cde00a3%40googlegroups.com.
