Table 2: Classification based on the similarity of rewriting rules.

Classification of rules Isomorphic Isomorphic Isomorphic Isomorphic
Depth #0 Depth #1 Depth #2 Depth #3

Class #1(19)
(4)
(4)
(20)
(8) (3) )
) 1) )
) 1) )
) 1)
) 1)
) 1)
)
(5)

Class #2 (48) null (4) ) )
Class #3 (4) ) )
Class #4 (20) ) )
Class #5 (48) null ) )
Class #6 ) )
Class #7 ) )
Class #8 (5) )
Class #9 (4) )
Class #10 (4) )
Class #11 (20) )
Class #12 (48) null )
Class #13 (5)
Class #14 (4)
Class #15 (4)
Class #16 (20)
Class #17 (48) null