Siberian Mathematical Journal ( IF 0.7 ) Pub Date : 2021-05-27 , DOI: 10.1134/s0037446621030198 V. A. Sharafutdinov
The Radon transform \( R \) maps a function \( f \) on \( {}^{n} \) to the family of the integrals of \( f \) over all hyperplanes. The classical Reshetnyak formula (also called the Plancherel formula for the Radon transform) states that \( \|f\|_{L^{2}({}^{n})}=\|Rf\|_{H^{(n-1)/2}_{(n-1)/2}({𝕊}^{n-1}\times{})} \), where \( \|\cdot\|_{H^{(n-1)/2}_{(n-1)/2}({𝕊}^{n-1}\times{})} \) is some special norm. The formula extends the Radon transform to the bijective Hilbert space isometry \( R:L^{2}({}^{n})\rightarrow H^{(n-1)/2}_{(n-1)/2,e}({𝕊}^{n-1}\times{}) \). Given reals \( r \), \( s \), and \( t>-n/2 \), we introduce the Sobolev type spaces \( H^{(r,s)}_{t}({}^{n}) \) and \( H^{(r,s)}_{t,e}({𝕊}^{n-1}\times{}) \) and prove the version of the Reshetnyak formula: \( \|f\|_{H^{(r,s)}_{t}({}^{n})}=\|Rf\|_{H^{(r,(s+n-1)/2)}_{t+(n-1)/2}({𝕊}^{n-1}\times{})} \). The formula extends the Radon transform to the bijective Hilbert space isometry \( R:H^{(r,s)}_{t}({}^{n})\rightarrow H^{(r,s+(n-1)/2)}_{t+(n-1)/2,e}({𝕊}^{n-1}\times{}) \). If \( r\geq 0 \) and \( s\geq 0 \) are integers then \( H^{(r,s)}_{0,e}({𝕊}^{n-1}\times{}) \) consists of the even functions \( \varphi(\xi,p) \) with square integrable derivatives of order \( \leq r \) with respect to \( \xi \) and order \( \leq s \) with respect to \( p \).
中文翻译:
索博列夫空间上的氡变换
Radon变换 \(R \)映射函数 \(F \)上 \({} ^ {N} \) 家族的积分的 \(F \)在所有的超平面。经典的 Reshetnyak 公式(也称为 Radon 变换的 Plancherel 公式)指出 \( \|f\|_{L^{2}({}^{n})}=\|Rf\|_{H ^{(n-1)/2}_{(n-1)/2}({𝕊}^{n-1}\times{})} \),其中 \( \|\cdot\|_ {H^{(n-1)/2}_{(n-1)/2}({𝕊}^{n-1}\times{})} \) 是一些特殊的范数。该公式将Radon变换扩展到双射希尔伯特空间等距 \( R:L^{2}({}^{n})\rightarrow H^{(n-1)/2}_{(n-1) / 2,e}({𝕊} ^ {n-1} \ times {})\)。给定实数 \( r \)、\( s \)和\( t>-n/2 \),我们引入了 Sobolev 类型空间 \( H^{(r,s)}_{t}({}^{n}) \)和\( H^{( r,s)}_{t,e}({𝕊}^{n-1}\times{}) \) 并证明 Reshetnyak 公式的版本: \( \|f\|_{H^{ (r,s)}_{t}({}^{n})}=\|Rf\|_{H^{(r,(s+n-1)/2)}_{t+(n -1)/2}({𝕊}^{n-1}\times{})} \) . 该公式将 Radon 变换扩展到双射 Hilbert 空间等距 \( R:H^{(r,s)}_{t}({}^{n})\rightarrow H^{(r,s+(n- 1)/2)}_{t+(n-1)/2,e}({𝕊}^{n-1}\times{}) \)。如果\( r\geq 0 \)和\( s\geq 0 \)是整数,则\( H^{(r,s)}_{0,e}({𝕊}^{n-1}\times {}) \) 由偶函数\( \varphi(\xi,p) \) 用的顺序平方可积的衍生物 \(\当量r \)相对于 \(\ XI \)和顺序 \(\当量小号\)与尊重 \(第\) 。