6: Surjection

<The previous article in this series | The table of contents of this series | The next article in this series>

A definition of surjection

---

Topics

About: set

---

The table of contents of this article

• Starting Context
• Target Context
• Orientation
• Main Body
• 1: Definition

---

Starting Context

• The reader knows a definition of set.
• The reader knows a definition of map.

---

Target Context

• The reader will have a definition of surjection.

---

Orientation

There is a list of definitions discussed so far in this site.

There is a list of propositions discussed so far in this site.

---

Main Body

---

1: Definition

For any sets, $S_1$ and $S_2$, any map, $f:S_1\to S_2$, such that for each $s_2\in S_2$, there is an $s_1\in S_1$ such that $s_2=f(s_1)$

---

References

<The previous article in this series | The table of contents of this series | The next article in this series>