1、In mathematics, a surjection is a function that maps every element in the codomain to at least one element in the domain.
在数学中，满射是一种函数，它将值域中的每个元素映射到至少一个定义域中的元素。

2、A surjection is also known as an "onto" function, as it covers the entire range of the codomain.
满射也被称为"onto"函数，因为它覆盖了整个值域的范围。