Hi Johannes,
To solve a Linear Matrix Inequality (LMI) problem in MATLAB where decision variables are interdependent (e.g., one matrix entry in your LMI consists of variables that are subtracted from each other, like X = [x1 x2-x3; x5-x4 0]), you need to use the LMI Lab. The "lmivar" function is used to define the structure of the LMI variables, but it does not directly handle the arithmetic operations between decision variables. Instead, you may use the "lmiterm" function to specify the terms of your LMI, including any interdependencies between variables.
Please refer to the documentation for more information on "lmiterm" function -
More information on how to declare decision variables as interdependent -
https://www.mathworks.com/help/robust/ug/advanced-topics.html
Hope this helps.
