On 2D Inverse Problems/Radial

The solution of the following layered radially symmetric inverse problems involves a number of classical mathematical tools & objects. Dissertation Four IV Stieltjes continued fractures Solutions of the problem Cauchy matrices Why It Matters for EIT When reconstructing images of an object (like a cross-section of a human torso or a piece of fruit), simple concentric layers (the onion model) are rarely enough because internal conductivity varies angularly as well as radially. The block-circulant structure using the shift matrix $S$ handles that rotational symmetry, allowing you to decouple the angular modes (Fourier modes) and solve the inverse problem layer by layer or mode by mode.