YES After renaming modulo { A->0, b->1, a->2, B->3 }, it remains to prove termination of the 4-rule system { 0 1 -> 1 2 3 0 , 3 2 -> 2 1 0 3 , 0 2 -> , 3 1 -> } Applying sparse 2-tiling [Hofbauer/Geser/Waldmann, FSCD 2019]. After renaming modulo { (0,0)->0, (0,1)->1, (1,0)->2, (1,2)->3, (2,3)->4, (3,0)->5, (1,1)->6, (0,2)->7, (1,3)->8, (0,3)->9, (1,5)->10, (0,5)->11, (2,0)->12, (2,1)->13, (3,1)->14, (3,2)->15, (2,2)->16, (3,3)->17, (2,5)->18, (3,5)->19 }, it remains to prove termination of the 80-rule system { 0 1 2 -> 1 3 4 5 0 , 0 1 6 -> 1 3 4 5 1 , 0 1 3 -> 1 3 4 5 7 , 0 1 8 -> 1 3 4 5 9 , 0 1 10 -> 1 3 4 5 11 , 2 1 2 -> 6 3 4 5 0 , 2 1 6 -> 6 3 4 5 1 , 2 1 3 -> 6 3 4 5 7 , 2 1 8 -> 6 3 4 5 9 , 2 1 10 -> 6 3 4 5 11 , 12 1 2 -> 13 3 4 5 0 , 12 1 6 -> 13 3 4 5 1 , 12 1 3 -> 13 3 4 5 7 , 12 1 8 -> 13 3 4 5 9 , 12 1 10 -> 13 3 4 5 11 , 5 1 2 -> 14 3 4 5 0 , 5 1 6 -> 14 3 4 5 1 , 5 1 3 -> 14 3 4 5 7 , 5 1 8 -> 14 3 4 5 9 , 5 1 10 -> 14 3 4 5 11 , 9 15 12 -> 7 13 2 9 5 , 9 15 13 -> 7 13 2 9 14 , 9 15 16 -> 7 13 2 9 15 , 9 15 4 -> 7 13 2 9 17 , 9 15 18 -> 7 13 2 9 19 , 8 15 12 -> 3 13 2 9 5 , 8 15 13 -> 3 13 2 9 14 , 8 15 16 -> 3 13 2 9 15 , 8 15 4 -> 3 13 2 9 17 , 8 15 18 -> 3 13 2 9 19 , 4 15 12 -> 16 13 2 9 5 , 4 15 13 -> 16 13 2 9 14 , 4 15 16 -> 16 13 2 9 15 , 4 15 4 -> 16 13 2 9 17 , 4 15 18 -> 16 13 2 9 19 , 17 15 12 -> 15 13 2 9 5 , 17 15 13 -> 15 13 2 9 14 , 17 15 16 -> 15 13 2 9 15 , 17 15 4 -> 15 13 2 9 17 , 17 15 18 -> 15 13 2 9 19 , 0 7 12 -> 0 , 0 7 13 -> 1 , 0 7 16 -> 7 , 0 7 4 -> 9 , 0 7 18 -> 11 , 2 7 12 -> 2 , 2 7 13 -> 6 , 2 7 16 -> 3 , 2 7 4 -> 8 , 2 7 18 -> 10 , 12 7 12 -> 12 , 12 7 13 -> 13 , 12 7 16 -> 16 , 12 7 4 -> 4 , 12 7 18 -> 18 , 5 7 12 -> 5 , 5 7 13 -> 14 , 5 7 16 -> 15 , 5 7 4 -> 17 , 5 7 18 -> 19 , 9 14 2 -> 0 , 9 14 6 -> 1 , 9 14 3 -> 7 , 9 14 8 -> 9 , 9 14 10 -> 11 , 8 14 2 -> 2 , 8 14 6 -> 6 , 8 14 3 -> 3 , 8 14 8 -> 8 , 8 14 10 -> 10 , 4 14 2 -> 12 , 4 14 6 -> 13 , 4 14 3 -> 16 , 4 14 8 -> 4 , 4 14 10 -> 18 , 17 14 2 -> 5 , 17 14 6 -> 14 , 17 14 3 -> 15 , 17 14 8 -> 17 , 17 14 10 -> 19 } The system was filtered by the following matrix interpretation of type E_J with J = {1,...,2} and dimension 2: 0 is interpreted by / \ | 1 1 | | 0 1 | \ / 1 is interpreted by / \ | 1 2 | | 0 1 | \ / 2 is interpreted by / \ | 1 0 | | 0 1 | \ / 3 is interpreted by / \ | 1 0 | | 0 1 | \ / 4 is interpreted by / \ | 1 0 | | 0 1 | \ / 5 is interpreted by / \ | 1 0 | | 0 1 | \ / 6 is interpreted by / \ | 1 1 | | 0 1 | \ / 7 is interpreted by / \ | 1 1 | | 0 1 | \ / 8 is interpreted by / \ | 1 0 | | 0 1 | \ / 9 is interpreted by / \ | 1 0 | | 0 1 | \ / 10 is interpreted by / \ | 1 0 | | 0 1 | \ / 11 is interpreted by / \ | 1 0 | | 0 1 | \ / 12 is interpreted by / \ | 1 0 | | 0 1 | \ / 13 is interpreted by / \ | 1 0 | | 0 1 | \ / 14 is interpreted by / \ | 1 1 | | 0 1 | \ / 15 is interpreted by / \ | 1 2 | | 0 1 | \ / 16 is interpreted by / \ | 1 1 | | 0 1 | \ / 17 is interpreted by / \ | 1 1 | | 0 1 | \ / 18 is interpreted by / \ | 1 0 | | 0 1 | \ / 19 is interpreted by / \ | 1 0 | | 0 1 | \ / After renaming modulo { 0->0, 1->1, 2->2, 3->3, 4->4, 5->5, 6->6, 7->7, 14->8, 9->9, 15->10, 13->11, 16->12, 17->13 }, it remains to prove termination of the 28-rule system { 0 1 2 -> 1 3 4 5 0 , 0 1 6 -> 1 3 4 5 1 , 0 1 3 -> 1 3 4 5 7 , 2 1 2 -> 6 3 4 5 0 , 2 1 6 -> 6 3 4 5 1 , 2 1 3 -> 6 3 4 5 7 , 5 1 2 -> 8 3 4 5 0 , 5 1 6 -> 8 3 4 5 1 , 5 1 3 -> 8 3 4 5 7 , 9 10 11 -> 7 11 2 9 8 , 9 10 12 -> 7 11 2 9 10 , 9 10 4 -> 7 11 2 9 13 , 4 10 11 -> 12 11 2 9 8 , 4 10 12 -> 12 11 2 9 10 , 4 10 4 -> 12 11 2 9 13 , 13 10 11 -> 10 11 2 9 8 , 13 10 12 -> 10 11 2 9 10 , 13 10 4 -> 10 11 2 9 13 , 0 7 11 -> 1 , 2 7 11 -> 6 , 5 7 11 -> 8 , 5 7 12 -> 10 , 5 7 4 -> 13 , 9 8 2 -> 0 , 9 8 6 -> 1 , 9 8 3 -> 7 , 4 8 3 -> 12 , 13 8 3 -> 10 } Applying the dependency pairs transformation. After renaming modulo { (0,true)->0, (1,false)->1, (2,false)->2, (4,true)->3, (5,false)->4, (0,false)->5, (5,true)->6, (6,false)->7, (3,false)->8, (7,false)->9, (2,true)->10, (9,true)->11, (10,false)->12, (11,false)->13, (9,false)->14, (8,false)->15, (12,false)->16, (4,false)->17, (13,false)->18, (13,true)->19 }, it remains to prove termination of the 72-rule system { 0 1 2 -> 3 4 5 , 0 1 2 -> 6 5 , 0 1 2 -> 0 , 0 1 7 -> 3 4 1 , 0 1 7 -> 6 1 , 0 1 8 -> 3 4 9 , 0 1 8 -> 6 9 , 10 1 2 -> 3 4 5 , 10 1 2 -> 6 5 , 10 1 2 -> 0 , 10 1 7 -> 3 4 1 , 10 1 7 -> 6 1 , 10 1 8 -> 3 4 9 , 10 1 8 -> 6 9 , 6 1 2 -> 3 4 5 , 6 1 2 -> 6 5 , 6 1 2 -> 0 , 6 1 7 -> 3 4 1 , 6 1 7 -> 6 1 , 6 1 8 -> 3 4 9 , 6 1 8 -> 6 9 , 11 12 13 -> 10 14 15 , 11 12 13 -> 11 15 , 11 12 16 -> 10 14 12 , 11 12 16 -> 11 12 , 11 12 17 -> 10 14 18 , 11 12 17 -> 11 18 , 11 12 17 -> 19 , 3 12 13 -> 10 14 15 , 3 12 13 -> 11 15 , 3 12 16 -> 10 14 12 , 3 12 16 -> 11 12 , 3 12 17 -> 10 14 18 , 3 12 17 -> 11 18 , 3 12 17 -> 19 , 19 12 13 -> 10 14 15 , 19 12 13 -> 11 15 , 19 12 16 -> 10 14 12 , 19 12 16 -> 11 12 , 19 12 17 -> 10 14 18 , 19 12 17 -> 11 18 , 19 12 17 -> 19 , 6 9 17 -> 19 , 11 15 2 -> 0 , 5 1 2 ->= 1 8 17 4 5 , 5 1 7 ->= 1 8 17 4 1 , 5 1 8 ->= 1 8 17 4 9 , 2 1 2 ->= 7 8 17 4 5 , 2 1 7 ->= 7 8 17 4 1 , 2 1 8 ->= 7 8 17 4 9 , 4 1 2 ->= 15 8 17 4 5 , 4 1 7 ->= 15 8 17 4 1 , 4 1 8 ->= 15 8 17 4 9 , 14 12 13 ->= 9 13 2 14 15 , 14 12 16 ->= 9 13 2 14 12 , 14 12 17 ->= 9 13 2 14 18 , 17 12 13 ->= 16 13 2 14 15 , 17 12 16 ->= 16 13 2 14 12 , 17 12 17 ->= 16 13 2 14 18 , 18 12 13 ->= 12 13 2 14 15 , 18 12 16 ->= 12 13 2 14 12 , 18 12 17 ->= 12 13 2 14 18 , 5 9 13 ->= 1 , 2 9 13 ->= 7 , 4 9 13 ->= 15 , 4 9 16 ->= 12 , 4 9 17 ->= 18 , 14 15 2 ->= 5 , 14 15 7 ->= 1 , 14 15 8 ->= 9 , 17 15 8 ->= 16 , 18 15 8 ->= 12 } The system was filtered by the following matrix interpretation of type E_J with J = {1,...,2} and dimension 2: 0 is interpreted by / \ | 1 0 | | 0 1 | \ / 1 is interpreted by / \ | 1 1 | | 0 1 | \ / 2 is interpreted by / \ | 1 1 | | 0 1 | \ / 3 is interpreted by / \ | 1 0 | | 0 1 | \ / 4 is interpreted by / \ | 1 0 | | 0 1 | \ / 5 is interpreted by / \ | 1 1 | | 0 1 | \ / 6 is interpreted by / \ | 1 0 | | 0 1 | \ / 7 is interpreted by / \ | 1 1 | | 0 1 | \ / 8 is interpreted by / \ | 1 0 | | 0 1 | \ / 9 is interpreted by / \ | 1 0 | | 0 1 | \ / 10 is interpreted by / \ | 1 0 | | 0 1 | \ / 11 is interpreted by / \ | 1 0 | | 0 1 | \ / 12 is interpreted by / \ | 1 1 | | 0 1 | \ / 13 is interpreted by / \ | 1 0 | | 0 1 | \ / 14 is interpreted by / \ | 1 0 | | 0 1 | \ / 15 is interpreted by / \ | 1 0 | | 0 1 | \ / 16 is interpreted by / \ | 1 1 | | 0 1 | \ / 17 is interpreted by / \ | 1 1 | | 0 1 | \ / 18 is interpreted by / \ | 1 1 | | 0 1 | \ / 19 is interpreted by / \ | 1 0 | | 0 1 | \ / After renaming modulo { 5->0, 1->1, 2->2, 8->3, 17->4, 4->5, 7->6, 9->7, 15->8, 14->9, 12->10, 13->11, 16->12, 18->13 }, it remains to prove termination of the 28-rule system { 0 1 2 ->= 1 3 4 5 0 , 0 1 6 ->= 1 3 4 5 1 , 0 1 3 ->= 1 3 4 5 7 , 2 1 2 ->= 6 3 4 5 0 , 2 1 6 ->= 6 3 4 5 1 , 2 1 3 ->= 6 3 4 5 7 , 5 1 2 ->= 8 3 4 5 0 , 5 1 6 ->= 8 3 4 5 1 , 5 1 3 ->= 8 3 4 5 7 , 9 10 11 ->= 7 11 2 9 8 , 9 10 12 ->= 7 11 2 9 10 , 9 10 4 ->= 7 11 2 9 13 , 4 10 11 ->= 12 11 2 9 8 , 4 10 12 ->= 12 11 2 9 10 , 4 10 4 ->= 12 11 2 9 13 , 13 10 11 ->= 10 11 2 9 8 , 13 10 12 ->= 10 11 2 9 10 , 13 10 4 ->= 10 11 2 9 13 , 0 7 11 ->= 1 , 2 7 11 ->= 6 , 5 7 11 ->= 8 , 5 7 12 ->= 10 , 5 7 4 ->= 13 , 9 8 2 ->= 0 , 9 8 6 ->= 1 , 9 8 3 ->= 7 , 4 8 3 ->= 12 , 13 8 3 ->= 10 } The system is trivially terminating.