User blog comment:Mh314159/FOX notation/@comment-39585023-20191205111828/@comment-39585023-20191206110333

I was trying to define "[a]‹S›n(x) = [a]‹T›[a]‹T›...(x)(x) where the dots indicate n layers of subscript ending in [a]‹T›(x)" but I tried to use inductive definition and avoid using ellipsis. So what should my inductive definition look like, or do you think it's okay to use the ellipsis definition?