Peetre's inequality

In mathematics, Peetre's inequality, named after Jaak Peetre, says that for any real number t and any vectors x and y in Rⁿ, the following inequality holds:

\left( \frac{1+|x|^2}{1+|y|^2} \right)^t \le 2^{|t|} (1+|x-y|^2)^{|t|}.

References

Chazarain, J.; Piriou, A. (2011), Introduction to the Theory of Linear Partial Differential Equations, Studies in Mathematics and its Applications, Elsevier, p. 90, ISBN 9780080875354 .
Ruzhansky, Michael; Turunen, Ville (2009), Pseudo-Differential Operators and Symmetries: Background Analysis and Advanced Topics, Pseudo-Differential Operators, Theory and Applications 2, Springer, p. 321, ISBN 9783764385132 .
Saint Raymond, Xavier (1991), Elementary Introduction to the Theory of Pseudodifferential Operators, Studies in Advanced Mathematics 3, CRC Press, p. 21, ISBN 9780849371585 .

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