Hello, I would like to know the specific theory of linear Minumum norm in source computer in brainstorm. However, I did not find the corresponding mathematic theory on the Internet. I hope the developer can provide some references so that I can elaborate it in the paper.

I am sorry, I carefully read the tutorials introduce and the reference of Sylvain Baillet, but I cannot find the specific foumulas and theories to explain L1 Minumum norm algorithm

You are probably referring to L2 - not L1 - minimum-norm estimates. The basic formulation is explained in the following paper:

https://www.researchgate.net/publication/3321395_Electromagnetic_Brain_Mapping

The actual Brainstorm implementation is identical to that explained in the MNE manual:

Hope this helps,

I have find the question answers, thank you very much