User blog comment:Ikosarakt1/BEAN is much stronger/@comment-1605058-20130612191353/@comment-5150073-20130612192422

Under &(LX,1) I meant LX,1-typed array of operator. For example, &(L,1) means &, &(L,2) means &&, &(L2,1) means @ - this is legiattic "array of". Generally, &(A) means the array of operator repeated application of which lead to A-space.

With \_[, there is a mistake, I must fix it, but now I'm trying to minimize MathJax in my list (slow loading makes unconvenient).