# Whitney’s extension

Xem 1-3 trên 3 kết quả Whitney’s extension
• ### Đề tài "A sharp form of Whitney’s extension theorem "

In this paper, we solve the following extension problem. Problem 1. Suppose we are given a function f : E → R, where E is a given subset of Rn. How can we decide whether f extends to a Cm−1,1 function F on Rn ? Here, m ≥ 1 is given. As usual, Cm−1,1 denotes the space of functions whose (m − 1)rst derivatives are Lipschitz 1. We make no assumption on the set E or the function f. This problem, with Cm in place of Cm−1,1, goes back to Whitney [15], [16], [17]. To answer it, we prove the following sharp form of the Whitney extension theorem....

• ### Đề tài " Whitney’s extension problem for Cm "

Let f be a real-valued function on a compact set in Rn , and let m be a positive integer. We show how to decide whether f extends to a Cm function on Rn . Introduction Continuing from [F2], we answer the following question (“Whitney’s extension problem”; see [hW2]). Question 1. Let ϕ be a real-valued function deﬁned on a compact subset E of Rn . How can we tell whether there exists F ∈ C m (Rn ) with F = ϕ on E? Here, m ≥ 1 is given, and C m (Rn ) denotes the space...