Surjective proof & finding inverse

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SUMMARY

The function g: ℕ → ℕ defined by g(x) = ⌊(3x + 1)/3⌋ is proven to be surjective. The proof involves demonstrating that for every y in the codomain, there exists an x in the domain such that g(x) = y. The inverse function is correctly identified as g⁻¹(y) = ⌊(3y - 1)/3⌋, confirming the bijective nature of g. This discussion emphasizes the importance of understanding the properties of functions in mathematical proofs.

PREREQUISITES
  • Understanding of bijective functions
  • Familiarity with the floor function (⌊y⌋)
  • Basic knowledge of natural numbers (ℕ)
  • Concept of surjectivity in functions
NEXT STEPS
  • Study the properties of bijective functions in detail
  • Learn about the floor function and its applications
  • Explore proofs of surjectivity for various functions
  • Investigate inverse functions and their significance in mathematics
USEFUL FOR

Mathematicians, students studying advanced algebra, and anyone interested in understanding function properties and proofs in mathematics.

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prove the function ## g: \mathbb{N} \rightarrow \mathbb{N} ## ## g(x) = \left[\dfrac{3x+1}{3} \right] ## where ## [y] ## is the maximum integer part of r belonging to integers s.t. r less than or equal to y is surjective and find it's inverse

I know this function is bijective, but how do I prove it's surjective? Could I just say g(x) = y ## \left[\dfrac{3x+1}{3} \right] = y ## so ## x = \left[\dfrac{3y-1}{3} \right ] ## and say that ## g^{-1}(x) = \left[\dfrac{3y-1}{3} \right ] ##
 
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Yikes, talk about last-minute.

It may help you to split up that fraction.
 
FeDeX_LaTeX said:
Yikes, talk about last-minute.

It may help you to split up that fraction.

last-minute what?
 

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