let str_sub_ls_clot_dbg table sub (ls : t_equal) : string =
let rec help str = function
| (n,t)::tail ->
let t_clot = clot_light sub t in
help (str^(str_term_dbg table (Var n))^" <- "^(str_term_dbg table t_clot)^"\n") tail
| [] -> str
in
if ls = [] then "empty subst\n" else help "" ls