Thanks for the clarification. All my concerns and doubt about the proposal are finished and we are good to go. I will be sharing the proposal soon here titled : "Boost.uBLAS: Stabilizing, Enhancing and C++20-ification". Each phase will have one of the thing mentioned here completed. During first phase, I will be stabilizing the code that we worked last year, notably the static_extent, sub tensor and other interfaces. Second phase will be enhancing which will involve producing a new matrix and vector type based on tensor, Finally I would be implementing the C++20 concepts to replace all meta functions and restricting the template parameters. This will be as per your wish could be carried on a different branch.