this query gets the dominating sets in a network. so for example given a network

A<----->B
B<----->C
B<----->D
C<----->E
D<----->C
D<----->E
F<----->E

it returns
B,E
B,F
A,E
but it doesn't work for large data because i'm using string methods in my result. i have been trying to remove the string methods and return a view or something but to no avail

With t as (select 'A' as per1, 'B' as per2 from dual union all
         select 'B','C' from dual union all
         select 'B','D' from dual union all
         select 'C','B' from dual union all
         select 'C','E' from dual union all
         select 'D','C' from dual union all
         select 'D','E' from dual union all
         select 'E','C' from dual union all
         select 'E','D' from dual union all
         select 'F','E' from dual)
 ,t2 as (select distinct least(per1, per2) as per1, greatest(per1, per2) as per2 from t union
       select distinct greatest(per1, per2) as per1, least(per1, per2) as per1 from t)
 ,t3 as (select per1, per2, row_number() over (partition by per1 order by per2) as rn from t2)
 ,people as (select per, row_number() over (order by per) rn
             from (select distinct per1 as per from t union
                   select distinct per2 from t)
            )
  ,comb   as (select sys_connect_by_path(per,',')||',' as p
              from   people
              connect by rn > prior rn
             )
  ,find   as (select p, per2, count(*) over (partition by p) as cnt
             from (
                   select distinct comb.p, t3.per2
                   from   comb, t3
                   where  instr(comb.p, ','||t3.per1||',') > 0 or instr(comb.p, ','||t3.per2||',') > 0
                  )
            )
 ,rnk as (select p, rank() over (order by length(p)) as rnk
          from find
          where cnt = (select count(*) from people)
          order by rnk
         )  select distinct trim(',' from p) as p from rnk  where rnk.rnk = 1`