Question 3: Suppose that A, B, and C are three sets (possibly infinite). Show that if f: A → B is an injection, and g: B
-
- Site Admin
- Posts: 899603
- Joined: Mon Aug 02, 2021 8:13 am
Question 3: Suppose that A, B, and C are three sets (possibly infinite). Show that if f: A → B is an injection, and g: B
Question 3: Suppose that A, B, and C are three sets (possibly infinite). Show that if f: A → B is an injection, and g: B → C is an injection, then go f is an injection from A to C. Note: A consequence of this is that if |A|≤ B and B| ≤ C, then |A|≤|C|. This consequence only becomes interesting when A, B, and C are infinite, since otherwise A, B, and C are just integers.