Condition for a function to be injective

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SUMMARY

For a function f: X -> Y to be injective, each element in the domain X must map to a unique element in the codomain Y. This means that no two distinct elements in X can share the same image in Y. The discussion clarifies that if an element in X does not have an image in Y, then f cannot be considered a valid function, and thus cannot be injective.

PREREQUISITES
  • Understanding of functions and mappings in set theory
  • Knowledge of injective functions and their properties
  • Familiarity with the concepts of domain and codomain
  • Basic mathematical notation and terminology
NEXT STEPS
  • Study the definition and properties of injective functions in detail
  • Explore examples of injective and non-injective functions
  • Learn about the implications of functions not having images in their codomain
  • Investigate the relationship between injectivity and other types of functions, such as surjective and bijective
USEFUL FOR

Students studying mathematics, particularly those focusing on functions and their properties, as well as educators teaching foundational concepts in set theory and function analysis.

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Homework Statement


Do all the preimages on X need to have a (and of course I know only one but) image in Y for the f:x->y to be injective?
IS THE FOLLOWING FUNCTION INJECTIVE SINCE ONE ELEMENT OF FIRST DOES NOT HAVE ANY IMAGE
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Homework Equations





The Attempt at a Solution


Thank You.
 

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The way you have shown it, f is not a function from X to Y.
 
Thank you.
 

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