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Everything about Injective function

Function that preserves distinctness

In mathematics, an injective function (also known as injection, or one-to-one function) is a function f that maps distinct elements of its domain to distinct elements of its codomain; that is, x1 ≠ x2 implies f(x1) ≠ f(x2) (equivalently by contraposition, f(x1) = f(x2) implies x1 = x2). In other words, every element of the function's codomain is the image of at most one element of its domain. The term one-to-one function must not be confused with one-to-one correspondence that refers to bijective functions, which are functions such that each element in the codomain is an image of exactly one element in the domain. Wikipedia →

🧭 Start here: a 6-step reading path

  1. Read the overview: Injective functionA 5-minute orientation
  2. Pick up a classic book: Decision Making HandbookThe most-reprinted book on the subject
  3. Read the landmark paper: Properly injective spaces and function spacesCited 64 times
  4. Go sideways: Bijection, injection and surjectionA closely related topic
  5. Go sideways: Surjective functionA closely related topic

📖 Definitions

Noun Synonym of injection (“a relation on sets (X,Y) that associates each element of Y with at most one element of X.”).

🏆 Landmark papers (most cited)

📚 Books worth reading

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