system
Given the following post, respond as if you're commenting on Reddit:
human
Suppose we have two black holes, one that formed from matter and one that formed from an equal amount of antimatter. If they were to collide and merge, would they merge normally, or would there be some difference noticeable to an outside observer?

Also, if I may further the question a bit: would it be possible for infalling matter (stuff that just passed through the event horizon) from one of the black holes to ever "meet up" with infalling anti-matter from the second black hole at some point within the horizon on the way towards the singularity?
gpt
It would be indistinguishable from two black holes made of matter merging. In general relativity black holes lose 'memory' of whatever makes them. It doesn't matter if it eats atoms, light, neutrinos, antimatter, dark matter, etc, they're all the same to a black hole. Some form of mass/energy goes in and the black hole mass increases, no questions asked.