# Functions. Basics

Algebra Level 4

Let $$f : A \to B$$ and $$g : B \to A$$ be functions such that $$g \circ f = Id_{A}$$. How many of the following statements are always true?

• $$f$$ is injective.
• $$g$$ is injective.
• $$f$$ is surjective.
• $$g$$ is surjective.
• $$f$$ is bijective.
• $$g$$ is bijective
×