- #1

Uncanny

- 36

- 1

- TL;DR Summary
- I’m curious why and where it’s necessary to explicitly state whether or not a set must be excluded from potentially being the empty set.

For instance, I attached two problems in the the thumbnail below. I’m curious why A cannot be the empty set in 18b, but A is not excluded from being the empty set in 17a.

In 17a, if A is empty, then all the hypothesis can be satisfied (the composition will be empty too, obviously), but g need not be equal to h. Am I right? If so, why isn’t this addressed in some problems, but is in others?

In 17a, if A is empty, then all the hypothesis can be satisfied (the composition will be empty too, obviously), but g need not be equal to h. Am I right? If so, why isn’t this addressed in some problems, but is in others?