YES After renaming modulo { a->0, b->1, c->2 }, it remains to prove termination of the 4-rule system { 0 -> , 0 0 -> 1 , 1 -> , 1 2 -> 2 2 2 1 0 } The system was reversed. After renaming modulo { 0->0, 1->1, 2->2 }, it remains to prove termination of the 4-rule system { 0 -> , 0 0 -> 1 , 1 -> , 2 1 -> 0 1 2 2 2 } Applying sparse 2-tiling [Hofbauer/Geser/Waldmann, FSCD 2019]. After renaming modulo { (0,0)->0, (0,1)->1, (0,2)->2, (0,4)->3, (1,0)->4, (1,1)->5, (1,2)->6, (1,4)->7, (2,0)->8, (2,1)->9, (2,2)->10, (2,4)->11, (3,0)->12, (3,1)->13, (3,2)->14, (3,4)->15 }, it remains to prove termination of the 64-rule system { 0 0 -> 0 , 0 1 -> 1 , 0 2 -> 2 , 0 3 -> 3 , 4 0 -> 4 , 4 1 -> 5 , 4 2 -> 6 , 4 3 -> 7 , 8 0 -> 8 , 8 1 -> 9 , 8 2 -> 10 , 8 3 -> 11 , 12 0 -> 12 , 12 1 -> 13 , 12 2 -> 14 , 12 3 -> 15 , 0 0 0 -> 1 4 , 0 0 1 -> 1 5 , 0 0 2 -> 1 6 , 0 0 3 -> 1 7 , 4 0 0 -> 5 4 , 4 0 1 -> 5 5 , 4 0 2 -> 5 6 , 4 0 3 -> 5 7 , 8 0 0 -> 9 4 , 8 0 1 -> 9 5 , 8 0 2 -> 9 6 , 8 0 3 -> 9 7 , 12 0 0 -> 13 4 , 12 0 1 -> 13 5 , 12 0 2 -> 13 6 , 12 0 3 -> 13 7 , 1 4 -> 0 , 1 5 -> 1 , 1 6 -> 2 , 1 7 -> 3 , 5 4 -> 4 , 5 5 -> 5 , 5 6 -> 6 , 5 7 -> 7 , 9 4 -> 8 , 9 5 -> 9 , 9 6 -> 10 , 9 7 -> 11 , 13 4 -> 12 , 13 5 -> 13 , 13 6 -> 14 , 13 7 -> 15 , 2 9 4 -> 0 1 6 10 10 8 , 2 9 5 -> 0 1 6 10 10 9 , 2 9 6 -> 0 1 6 10 10 10 , 2 9 7 -> 0 1 6 10 10 11 , 6 9 4 -> 4 1 6 10 10 8 , 6 9 5 -> 4 1 6 10 10 9 , 6 9 6 -> 4 1 6 10 10 10 , 6 9 7 -> 4 1 6 10 10 11 , 10 9 4 -> 8 1 6 10 10 8 , 10 9 5 -> 8 1 6 10 10 9 , 10 9 6 -> 8 1 6 10 10 10 , 10 9 7 -> 8 1 6 10 10 11 , 14 9 4 -> 12 1 6 10 10 8 , 14 9 5 -> 12 1 6 10 10 9 , 14 9 6 -> 12 1 6 10 10 10 , 14 9 7 -> 12 1 6 10 10 11 } 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 3 | | 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 2 | | 0 1 | \ / 5 is interpreted by / \ | 1 3 | | 0 1 | \ / 6 is interpreted by / \ | 1 0 | | 0 1 | \ / 7 is interpreted by / \ | 1 1 | | 0 1 | \ / 8 is interpreted by / \ | 1 2 | | 0 1 | \ / 9 is interpreted by / \ | 1 3 | | 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 1 | | 0 1 | \ / 14 is interpreted by / \ | 1 0 | | 0 1 | \ / 15 is interpreted by / \ | 1 0 | | 0 1 | \ / After renaming modulo { 4->0, 1->1, 5->2, 8->3, 9->4, 0->5, 6->6, 2->7, 10->8 }, it remains to prove termination of the 15-rule system { 0 1 -> 2 , 3 1 -> 4 , 0 5 1 -> 2 2 , 3 5 1 -> 4 2 , 1 0 -> 5 , 1 6 -> 7 , 7 4 0 -> 5 1 6 8 8 3 , 7 4 2 -> 5 1 6 8 8 4 , 7 4 6 -> 5 1 6 8 8 8 , 6 4 0 -> 0 1 6 8 8 3 , 6 4 2 -> 0 1 6 8 8 4 , 6 4 6 -> 0 1 6 8 8 8 , 8 4 0 -> 3 1 6 8 8 3 , 8 4 2 -> 3 1 6 8 8 4 , 8 4 6 -> 3 1 6 8 8 8 } Applying the dependency pairs transformation. After renaming modulo { (1,true)->0, (6,false)->1, (7,true)->2, (4,false)->3, (0,false)->4, (8,false)->5, (3,false)->6, (6,true)->7, (8,true)->8, (3,true)->9, (2,false)->10, (0,true)->11, (1,false)->12, (5,false)->13, (7,false)->14 }, it remains to prove termination of the 64-rule system { 0 1 -> 2 , 2 3 4 -> 0 1 5 5 6 , 2 3 4 -> 7 5 5 6 , 2 3 4 -> 8 5 6 , 2 3 4 -> 8 6 , 2 3 4 -> 9 , 2 3 10 -> 0 1 5 5 3 , 2 3 10 -> 7 5 5 3 , 2 3 10 -> 8 5 3 , 2 3 10 -> 8 3 , 2 3 1 -> 0 1 5 5 5 , 2 3 1 -> 7 5 5 5 , 2 3 1 -> 8 5 5 , 2 3 1 -> 8 5 , 2 3 1 -> 8 , 7 3 4 -> 11 12 1 5 5 6 , 7 3 4 -> 0 1 5 5 6 , 7 3 4 -> 7 5 5 6 , 7 3 4 -> 8 5 6 , 7 3 4 -> 8 6 , 7 3 4 -> 9 , 7 3 10 -> 11 12 1 5 5 3 , 7 3 10 -> 0 1 5 5 3 , 7 3 10 -> 7 5 5 3 , 7 3 10 -> 8 5 3 , 7 3 10 -> 8 3 , 7 3 1 -> 11 12 1 5 5 5 , 7 3 1 -> 0 1 5 5 5 , 7 3 1 -> 7 5 5 5 , 7 3 1 -> 8 5 5 , 7 3 1 -> 8 5 , 7 3 1 -> 8 , 8 3 4 -> 9 12 1 5 5 6 , 8 3 4 -> 0 1 5 5 6 , 8 3 4 -> 7 5 5 6 , 8 3 4 -> 8 5 6 , 8 3 4 -> 8 6 , 8 3 4 -> 9 , 8 3 10 -> 9 12 1 5 5 3 , 8 3 10 -> 0 1 5 5 3 , 8 3 10 -> 7 5 5 3 , 8 3 10 -> 8 5 3 , 8 3 10 -> 8 3 , 8 3 1 -> 9 12 1 5 5 5 , 8 3 1 -> 0 1 5 5 5 , 8 3 1 -> 7 5 5 5 , 8 3 1 -> 8 5 5 , 8 3 1 -> 8 5 , 8 3 1 -> 8 , 4 12 ->= 10 , 6 12 ->= 3 , 4 13 12 ->= 10 10 , 6 13 12 ->= 3 10 , 12 4 ->= 13 , 12 1 ->= 14 , 14 3 4 ->= 13 12 1 5 5 6 , 14 3 10 ->= 13 12 1 5 5 3 , 14 3 1 ->= 13 12 1 5 5 5 , 1 3 4 ->= 4 12 1 5 5 6 , 1 3 10 ->= 4 12 1 5 5 3 , 1 3 1 ->= 4 12 1 5 5 5 , 5 3 4 ->= 6 12 1 5 5 6 , 5 3 10 ->= 6 12 1 5 5 3 , 5 3 1 ->= 6 12 1 5 5 5 } 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 2 | | 0 1 | \ / 2 is interpreted by / \ | 1 1 | | 0 1 | \ / 3 is interpreted by / \ | 1 0 | | 0 1 | \ / 4 is interpreted by / \ | 1 2 | | 0 1 | \ / 5 is interpreted by / \ | 1 0 | | 0 1 | \ / 6 is interpreted by / \ | 1 0 | | 0 1 | \ / 7 is interpreted by / \ | 1 1 | | 0 1 | \ / 8 is interpreted by / \ | 1 1 | | 0 1 | \ / 9 is interpreted by / \ | 1 0 | | 0 1 | \ / 10 is interpreted by / \ | 1 2 | | 0 1 | \ / 11 is interpreted by / \ | 1 0 | | 0 1 | \ / 12 is interpreted by / \ | 1 0 | | 0 1 | \ / 13 is interpreted by / \ | 1 2 | | 0 1 | \ / 14 is interpreted by / \ | 1 2 | | 0 1 | \ / After renaming modulo { 4->0, 12->1, 10->2, 6->3, 3->4, 13->5, 1->6, 14->7, 5->8 }, it remains to prove termination of the 15-rule system { 0 1 ->= 2 , 3 1 ->= 4 , 0 5 1 ->= 2 2 , 3 5 1 ->= 4 2 , 1 0 ->= 5 , 1 6 ->= 7 , 7 4 0 ->= 5 1 6 8 8 3 , 7 4 2 ->= 5 1 6 8 8 4 , 7 4 6 ->= 5 1 6 8 8 8 , 6 4 0 ->= 0 1 6 8 8 3 , 6 4 2 ->= 0 1 6 8 8 4 , 6 4 6 ->= 0 1 6 8 8 8 , 8 4 0 ->= 3 1 6 8 8 3 , 8 4 2 ->= 3 1 6 8 8 4 , 8 4 6 ->= 3 1 6 8 8 8 } The system is trivially terminating.