Surjective Function: A to B Mapping

  • Thread starter d_b
  • Start date
  • Tags
    Surjective
In summary, a surjective function from A to B cannot have more than one element in B pointing to the same element in A. This is because, by definition, a function cannot have two images for one point in its domain. Additionally, the arrow from A to B signifies that the domain of the function is A and the range is a subset of B. It is also important to note that the correct spelling is "surjective."
  • #1
d_b
36
0
For a sirjective function from A--> B, I was just wondering if more than one elements in B can point to the same element in A if the function is surjective.
 
Physics news on Phys.org
  • #2
d_b said:
For a sirjective function from A--> B, I was just wondering if more than one elements in B can point to the same element in A if the function is surjective.

if I'm not wrong it can't follow because its not a function...I just want to make sure if I got it right
 
  • #3
Right. By definition, it can't be a function. It would mean that point in A would have two images, which is forbidden.
 
  • #4
Just a couple of points to clarify. If you write the arrow from A to B that means the domain of f is A and the range of f is a subset of B. Elements in B don't point to elements in A. And it's spelt surjective.
 

1. What is a surjective function?

A surjective function, also known as an onto function, is a type of mathematical function where every element in the range of the function is mapped to by at least one element in the domain. In other words, every element in the codomain has at least one pre-image in the domain.

2. What is the difference between a surjective function and an injective function?

The main difference between a surjective function and an injective function is that a surjective function may have multiple elements in the domain that map to the same element in the codomain, while an injective function ensures that each element in the domain maps to a unique element in the codomain.

3. How do you prove that a function is surjective?

In order to prove that a function is surjective, you must show that for every element in the codomain, there exists at least one element in the domain that maps to it. This can be done by either using the definition of a surjective function or by using a proof by contradiction.

4. Can a function be both surjective and injective?

Yes, a function can be both surjective and injective. This type of function is called a bijective function and it means that every element in the domain has a unique pre-image in the codomain and every element in the codomain has at least one pre-image in the domain.

5. How is a surjective function represented graphically?

A surjective function can be represented graphically by a line or curve that passes through every point in the codomain, indicating that each element in the codomain has at least one pre-image in the domain. This type of function is also known as a "one-to-one onto" function.

Similar threads

  • Linear and Abstract Algebra
Replies
10
Views
1K
  • Linear and Abstract Algebra
Replies
3
Views
1K
  • Topology and Analysis
Replies
8
Views
1K
  • Linear and Abstract Algebra
Replies
2
Views
855
  • Linear and Abstract Algebra
Replies
1
Views
978
  • Precalculus Mathematics Homework Help
Replies
4
Views
2K
Replies
5
Views
1K
  • Calculus and Beyond Homework Help
Replies
1
Views
599
  • Linear and Abstract Algebra
Replies
5
Views
1K
  • Linear and Abstract Algebra
Replies
10
Views
2K
Back
Top