Nice! It's fun to think about infinite sets, too.

**Puzzle.** If \\(A\\) and \\(B\\) are possibly infinite sets, and there's an injection \\(f: A \to B\\) and an injection \\(g: B \to A\\), is there a bijection between \\(A\\) and \\(B\\)?

**Puzzle.** If \\(A\\) and \\(B\\) are possibly infinite sets, and there's a surjection \\(f: A \to B\\) and an surjection \\(g: B \to A\\), is there a bijection between \\(A\\) and \\(B\\)?

**Puzzle.** If \\(A\\) and \\(B\\) are possibly infinite sets, and there's an injection \\(f: A \to B\\) and an injection \\(g: B \to A\\), is there a bijection between \\(A\\) and \\(B\\)?

**Puzzle.** If \\(A\\) and \\(B\\) are possibly infinite sets, and there's a surjection \\(f: A \to B\\) and an surjection \\(g: B \to A\\), is there a bijection between \\(A\\) and \\(B\\)?