YES
<?xml version="1.0"?>
<?xml-stylesheet type="text/xsl" href="cpfHTML.xsl"?><certificationProblem xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="cpf.xsd"><input><trsInput><trs><rules><rule><lhs><funapp><name>c</name><arg><funapp><name>a</name><arg><funapp><name>b</name><arg><funapp><name>a</name><arg><funapp><name>b</name><arg><var>x1</var></arg></funapp></arg></funapp></arg></funapp></arg></funapp></arg></funapp></lhs><rhs><funapp><name>a</name><arg><funapp><name>b</name><arg><funapp><name>a</name><arg><funapp><name>b</name><arg><funapp><name>b</name><arg><funapp><name>a</name><arg><funapp><name>b</name><arg><funapp><name>b</name><arg><funapp><name>c</name><arg><funapp><name>a</name><arg><funapp><name>b</name><arg><funapp><name>c</name><arg><funapp><name>a</name><arg><var>x1</var></arg></funapp></arg></funapp></arg></funapp></arg></funapp></arg></funapp></arg></funapp></arg></funapp></arg></funapp></arg></funapp></arg></funapp></arg></funapp></arg></funapp></arg></funapp></rhs></rule></rules></trs></trsInput></input><cpfVersion>2.1</cpfVersion><proof><trsTerminationProof><stringReversal><trs><rules><rule><lhs><funapp><name>b</name><arg><funapp><name>a</name><arg><funapp><name>b</name><arg><funapp><name>a</name><arg><funapp><name>c</name><arg><var>x1</var></arg></funapp></arg></funapp></arg></funapp></arg></funapp></arg></funapp></lhs><rhs><funapp><name>a</name><arg><funapp><name>c</name><arg><funapp><name>b</name><arg><funapp><name>a</name><arg><funapp><name>c</name><arg><funapp><name>b</name><arg><funapp><name>b</name><arg><funapp><name>a</name><arg><funapp><name>b</name><arg><funapp><name>b</name><arg><funapp><name>a</name><arg><funapp><name>b</name><arg><funapp><name>a</name><arg><var>x1</var></arg></funapp></arg></funapp></arg></funapp></arg></funapp></arg></funapp></arg></funapp></arg></funapp></arg></funapp></arg></funapp></arg></funapp></arg></funapp></arg></funapp></arg></funapp></rhs></rule></rules></trs><trsTerminationProof><bounds><type><match/></type><bound>3</bound><finalStates><state>4</state></finalStates><treeAutomaton><finalStates><state>4</state></finalStates><transitions><transition><lhs><state>124</state></lhs><rhs><state>85</state></rhs></transition><transition><lhs><state>96</state></lhs><rhs><state>43</state></rhs></transition><transition><lhs><state>68</state></lhs><rhs><state>26</state></rhs></transition><transition><lhs><state>66</state></lhs><rhs><state>83</state></rhs></transition><transition><lhs><state>63</state></lhs><rhs><state>111</state></rhs></transition><transition><lhs><state>54</state></lhs><rhs><state>21</state></rhs></transition><transition><lhs><state>54</state></lhs><rhs><state>57</state></rhs></transition><transition><lhs><state>38</state></lhs><rhs><state>20</state></rhs></transition><transition><lhs><state>32</state></lhs><rhs><state>4</state></rhs></transition><transition><lhs><state>32</state></lhs><rhs><state>23</state></rhs></transition><transition><lhs><state>32</state></lhs><rhs><state>21</state></rhs></transition><transition><lhs><state>30</state></lhs><rhs><state>37</state></rhs></transition><transition><lhs><state>30</state></lhs><rhs><state>55</state></rhs></transition><transition><lhs><state>27</state></lhs><rhs><state>41</state></rhs></transition><transition><lhs><state>4</state></lhs><rhs><state>19</state></rhs></transition><transition><lhs><name>c</name><height>0</height><state>4</state></lhs><rhs><state>4</state></rhs></transition><transition><lhs><name>b</name><height>2</height><state>90</state></lhs><rhs><state>91</state></rhs></transition><transition><lhs><name>b</name><height>2</height><state>48</state></lhs><rhs><state>49</state></rhs></transition><transition><lhs><name>b</name><height>2</height><state>58</state></lhs><rhs><state>59</state></rhs></transition><transition><lhs><name>b</name><height>2</height><state>93</state></lhs><rhs><state>94</state></rhs></transition><transition><lhs><name>b</name><height>2</height><state>51</state></lhs><rhs><state>52</state></rhs></transition><transition><lhs><name>b</name><height>2</height><state>56</state></lhs><rhs><state>57</state></rhs></transition><transition><lhs><name>b</name><height>2</height><state>61</state></lhs><rhs><state>62</state></rhs></transition><transition><lhs><name>b</name><height>2</height><state>86</state></lhs><rhs><state>87</state></rhs></transition><transition><lhs><name>b</name><height>2</height><state>44</state></lhs><rhs><state>45</state></rhs></transition><transition><lhs><name>b</name><height>2</height><state>59</state></lhs><rhs><state>60</state></rhs></transition><transition><lhs><name>b</name><height>2</height><state>84</state></lhs><rhs><state>85</state></rhs></transition><transition><lhs><name>b</name><height>2</height><state>89</state></lhs><rhs><state>90</state></rhs></transition><transition><lhs><name>b</name><height>2</height><state>42</state></lhs><rhs><state>43</state></rhs></transition><transition><lhs><name>b</name><height>2</height><state>47</state></lhs><rhs><state>48</state></rhs></transition><transition><lhs><name>b</name><height>2</height><state>62</state></lhs><rhs><state>63</state></rhs></transition><transition><lhs><name>b</name><height>2</height><state>87</state></lhs><rhs><state>88</state></rhs></transition><transition><lhs><name>b</name><height>2</height><state>45</state></lhs><rhs><state>46</state></rhs></transition><transition><lhs><name>b</name><height>2</height><state>65</state></lhs><rhs><state>66</state></rhs></transition><transition><lhs><name>a</name><height>0</height><state>4</state></lhs><rhs><state>4</state></rhs></transition><transition><lhs><name>c</name><height>2</height><state>63</state></lhs><rhs><state>64</state></rhs></transition><transition><lhs><name>c</name><height>2</height><state>66</state></lhs><rhs><state>67</state></rhs></transition><transition><lhs><name>c</name><height>2</height><state>91</state></lhs><rhs><state>92</state></rhs></transition><transition><lhs><name>c</name><height>2</height><state>49</state></lhs><rhs><state>50</state></rhs></transition><transition><lhs><name>c</name><height>2</height><state>94</state></lhs><rhs><state>95</state></rhs></transition><transition><lhs><name>c</name><height>2</height><state>52</state></lhs><rhs><state>53</state></rhs></transition><transition><lhs><name>b</name><height>0</height><state>4</state></lhs><rhs><state>4</state></rhs></transition><transition><lhs><name>a</name><height>2</height><state>85</state></lhs><rhs><state>86</state></rhs></transition><transition><lhs><name>a</name><height>2</height><state>95</state></lhs><rhs><state>96</state></rhs></transition><transition><lhs><name>a</name><height>2</height><state>43</state></lhs><rhs><state>44</state></rhs></transition><transition><lhs><name>a</name><height>2</height><state>53</state></lhs><rhs><state>54</state></rhs></transition><transition><lhs><name>a</name><height>2</height><state>83</state></lhs><rhs><state>84</state></rhs></transition><transition><lhs><name>a</name><height>2</height><state>88</state></lhs><rhs><state>89</state></rhs></transition><transition><lhs><name>a</name><height>2</height><state>41</state></lhs><rhs><state>42</state></rhs></transition><transition><lhs><name>a</name><height>2</height><state>46</state></lhs><rhs><state>47</state></rhs></transition><transition><lhs><name>a</name><height>2</height><state>64</state></lhs><rhs><state>65</state></rhs></transition><transition><lhs><name>a</name><height>2</height><state>57</state></lhs><rhs><state>58</state></rhs></transition><transition><lhs><name>a</name><height>2</height><state>67</state></lhs><rhs><state>68</state></rhs></transition><transition><lhs><name>a</name><height>2</height><state>92</state></lhs><rhs><state>93</state></rhs></transition><transition><lhs><name>a</name><height>2</height><state>50</state></lhs><rhs><state>51</state></rhs></transition><transition><lhs><name>a</name><height>2</height><state>55</state></lhs><rhs><state>56</state></rhs></transition><transition><lhs><name>a</name><height>2</height><state>60</state></lhs><rhs><state>61</state></rhs></transition><transition><lhs><name>b</name><height>1</height><state>23</state></lhs><rhs><state>24</state></rhs></transition><transition><lhs><name>b</name><height>1</height><state>26</state></lhs><rhs><state>27</state></rhs></transition><transition><lhs><name>b</name><height>1</height><state>29</state></lhs><rhs><state>30</state></rhs></transition><transition><lhs><name>b</name><height>1</height><state>22</state></lhs><rhs><state>23</state></rhs></transition><transition><lhs><name>b</name><height>1</height><state>20</state></lhs><rhs><state>21</state></rhs></transition><transition><lhs><name>b</name><height>1</height><state>25</state></lhs><rhs><state>26</state></rhs></transition><transition><lhs><name>b</name><height>3</height><state>115</state></lhs><rhs><state>116</state></rhs></transition><transition><lhs><name>b</name><height>3</height><state>118</state></lhs><rhs><state>119</state></rhs></transition><transition><lhs><name>b</name><height>3</height><state>121</state></lhs><rhs><state>122</state></rhs></transition><transition><lhs><name>b</name><height>3</height><state>114</state></lhs><rhs><state>115</state></rhs></transition><transition><lhs><name>b</name><height>3</height><state>112</state></lhs><rhs><state>113</state></rhs></transition><transition><lhs><name>b</name><height>3</height><state>117</state></lhs><rhs><state>118</state></rhs></transition><transition><lhs><name>c</name><height>1</height><state>27</state></lhs><rhs><state>28</state></rhs></transition><transition><lhs><name>c</name><height>1</height><state>30</state></lhs><rhs><state>31</state></rhs></transition><transition><lhs><name>c</name><height>3</height><state>119</state></lhs><rhs><state>120</state></rhs></transition><transition><lhs><name>c</name><height>3</height><state>122</state></lhs><rhs><state>123</state></rhs></transition><transition><lhs><name>a</name><height>1</height><state>28</state></lhs><rhs><state>29</state></rhs></transition><transition><lhs><name>a</name><height>1</height><state>21</state></lhs><rhs><state>22</state></rhs></transition><transition><lhs><name>a</name><height>1</height><state>31</state></lhs><rhs><state>32</state></rhs></transition><transition><lhs><name>a</name><height>1</height><state>19</state></lhs><rhs><state>20</state></rhs></transition><transition><lhs><name>a</name><height>1</height><state>24</state></lhs><rhs><state>25</state></rhs></transition><transition><lhs><name>a</name><height>1</height><state>37</state></lhs><rhs><state>38</state></rhs></transition><transition><lhs><name>a</name><height>3</height><state>120</state></lhs><rhs><state>121</state></rhs></transition><transition><lhs><name>a</name><height>3</height><state>113</state></lhs><rhs><state>114</state></rhs></transition><transition><lhs><name>a</name><height>3</height><state>123</state></lhs><rhs><state>124</state></rhs></transition><transition><lhs><name>a</name><height>3</height><state>111</state></lhs><rhs><state>112</state></rhs></transition><transition><lhs><name>a</name><height>3</height><state>116</state></lhs><rhs><state>117</state></rhs></transition></transitions></treeAutomaton><criterion><compatibility/></criterion></bounds></trsTerminationProof></stringReversal></trsTerminationProof></proof><origin><proofOrigin><tool><name>ttt2</name><version>ttt2 1.18 [hg: 65024290f751]</version><strategy>((if standard then var else fail) | con | (if srs then ((sleep -t 25?;rlab;(((( (if srs then arctic -dim 1 -ib 4 -ob 5 else fail) || (if srs then arctic -dim 2 -ib 2 -ob 3 else fail) || (if srs then arctic -dim 3 -ib 1 -ob 2 else fail) || (if srs then arctic -dim 3 -ib 2 -ob 2 else fail) || matrix -dim 1 -ib 5 -ob 8 || matrix -dim 2 -ib 3 -ob 4 || matrix -dim 3 -ib 2 -ob 3 || matrix -dim 3 -ib 1 -ob 2 || matrix -dim 4 -ib 1 -ob 2 || matrix -dim 5 -ib 1 -ob 1 || kbo -ib 3 -ob 4 || fail)[5]*);((dp;(edg -gtcap -nl[1.0]?;(sccs | ((sc || sc -rec -defs || sc -mulex -defs) || sct || {ur?;( matrix -dp -ur -dim 1 -ib 3 -ob 5 || matrix -dp -ur -dim 1 -ib 3 -ob 8 -rat 2 -db 1 || matrix -dp -ur -dim 1 -ib 4 -ob 10 -rat 4 -db 1 || matrix -dp -ur -dim 2 -ib 2 -ob 3 || matrix -dp -ur -dim 2 -ib 3 -ob 4 -rat 2 -db 0 || matrix -dp -ur -dim 3 -ib 1 -ob 3 || matrix -dp -ur -dim 3 -ib 2 -ob 3 || matrix -dp -ur -dim 3 -ib 2 -ob 3 -rat 2 -db 0 || matrix -dp -ur -dim 4 -ib 1 -ob 2 || lpo -ur -af || (arctic -dp -ur -dim 1 -ib 4 -ob 3[25] | arctic -dp -ur -dim 2 -ib 2 -ob 2[28] | arctic -dp -ur -dim 3 -ib 1 -ob 1[28] | arctic -dp -ur -dim 4 -ib 1 -ob 1[28] | fail) || (arctic -bz -dp -ur -dim 1 -ib 4 -ob 3[25] | arctic -bz -dp -ur -dim 2 -ib 2 -ob 2[28] | arctic -bz -dp -ur -dim 3 -ib 1 -ob 1[28] | arctic -bz -dp -ur -dim 4 -ib 1 -ob 1[28] | fail) || fail) } restore) )*[29])) || (bounds -cert || fail;(bounds -rfc -qc))))! || (( unfold || fail)*[7])!)[299])! || ((((( (if srs then arctic -dim 1 -ib 4 -ob 5 else fail) || (if srs then arctic -dim 2 -ib 2 -ob 3 else fail) || (if srs then arctic -dim 3 -ib 1 -ob 2 else fail) || (if srs then arctic -dim 3 -ib 2 -ob 2 else fail) || matrix -dim 1 -ib 5 -ob 8 || matrix -dim 2 -ib 3 -ob 4 || matrix -dim 3 -ib 2 -ob 3 || matrix -dim 3 -ib 1 -ob 2 || matrix -dim 4 -ib 1 -ob 2 || matrix -dim 5 -ib 1 -ob 1 || kbo -ib 3 -ob 4 || fail)[5]*);((dp;(edg -gtcap -nl[1.0]?;(sccs | ((sc || sc -rec -defs || sc -mulex -defs) || sct || {ur?;( matrix -dp -ur -dim 1 -ib 3 -ob 5 || matrix -dp -ur -dim 1 -ib 3 -ob 8 -rat 2 -db 1 || matrix -dp -ur -dim 1 -ib 4 -ob 10 -rat 4 -db 1 || matrix -dp -ur -dim 2 -ib 2 -ob 3 || matrix -dp -ur -dim 2 -ib 3 -ob 4 -rat 2 -db 0 || matrix -dp -ur -dim 3 -ib 1 -ob 3 || matrix -dp -ur -dim 3 -ib 2 -ob 3 || matrix -dp -ur -dim 3 -ib 2 -ob 3 -rat 2 -db 0 || matrix -dp -ur -dim 4 -ib 1 -ob 2 || lpo -ur -af || (arctic -dp -ur -dim 1 -ib 4 -ob 3[25] | arctic -dp -ur -dim 2 -ib 2 -ob 2[28] | arctic -dp -ur -dim 3 -ib 1 -ob 1[28] | arctic -dp -ur -dim 4 -ib 1 -ob 1[28] | fail) || (arctic -bz -dp -ur -dim 1 -ib 4 -ob 3[25] | arctic -bz -dp -ur -dim 2 -ib 2 -ob 2[28] | arctic -bz -dp -ur -dim 3 -ib 1 -ob 1[28] | arctic -bz -dp -ur -dim 4 -ib 1 -ob 1[28] | fail) || fail) } restore) )*[29])) || (bounds -cert || fail;(bounds -rfc -qc))))! || (( unfold || fail)*[7])!)[299])! || (rev?;((( (if srs then arctic -dim 1 -ib 4 -ob 5 else fail) || (if srs then arctic -dim 2 -ib 2 -ob 3 else fail) || (if srs then arctic -dim 3 -ib 1 -ob 2 else fail) || (if srs then arctic -dim 3 -ib 2 -ob 2 else fail) || matrix -dim 1 -ib 5 -ob 8 || matrix -dim 2 -ib 3 -ob 4 || matrix -dim 3 -ib 2 -ob 3 || matrix -dim 3 -ib 1 -ob 2 || matrix -dim 4 -ib 1 -ob 2 || matrix -dim 5 -ib 1 -ob 1 || kbo -ib 3 -ob 4 || fail)[5]*);((dp;(edg -gtcap -nl[1.0]?;(sccs | ((sc || sc -rec -defs || sc -mulex -defs) || sct || {ur?;( matrix -dp -ur -dim 1 -ib 3 -ob 5 || matrix -dp -ur -dim 1 -ib 3 -ob 8 -rat 2 -db 1 || matrix -dp -ur -dim 1 -ib 4 -ob 10 -rat 4 -db 1 || matrix -dp -ur -dim 2 -ib 2 -ob 3 || matrix -dp -ur -dim 2 -ib 3 -ob 4 -rat 2 -db 0 || matrix -dp -ur -dim 3 -ib 1 -ob 3 || matrix -dp -ur -dim 3 -ib 2 -ob 3 || matrix -dp -ur -dim 3 -ib 2 -ob 3 -rat 2 -db 0 || matrix -dp -ur -dim 4 -ib 1 -ob 2 || lpo -ur -af || (arctic -dp -ur -dim 1 -ib 4 -ob 3[25] | arctic -dp -ur -dim 2 -ib 2 -ob 2[28] | arctic -dp -ur -dim 3 -ib 1 -ob 1[28] | arctic -dp -ur -dim 4 -ib 1 -ob 1[28] | fail) || (arctic -bz -dp -ur -dim 1 -ib 4 -ob 3[25] | arctic -bz -dp -ur -dim 2 -ib 2 -ob 2[28] | arctic -bz -dp -ur -dim 3 -ib 1 -ob 1[28] | arctic -bz -dp -ur -dim 4 -ib 1 -ob 1[28] | fail) || fail) } restore) )*[29])) || (bounds -cert || fail;(bounds -rfc -qc))))![299])! ) else ((((( (if srs then arctic -dim 1 -ib 4 -ob 5 else fail) || (if srs then arctic -dim 2 -ib 2 -ob 3 else fail) || (if srs then arctic -dim 3 -ib 1 -ob 2 else fail) || (if srs then arctic -dim 3 -ib 2 -ob 2 else fail) || matrix -dim 1 -ib 5 -ob 8 || matrix -dim 2 -ib 3 -ob 4 || matrix -dim 3 -ib 2 -ob 3 || matrix -dim 3 -ib 1 -ob 2 || matrix -dim 4 -ib 1 -ob 2 || matrix -dim 5 -ib 1 -ob 1 || kbo -ib 3 -ob 4 || fail)[5]*);((dp;(edg -gtcap -nl[1.0]?;(sccs | ((sc || sc -rec -defs || sc -mulex -defs) || sct || {ur?;( matrix -dp -ur -dim 1 -ib 3 -ob 5 || matrix -dp -ur -dim 1 -ib 3 -ob 8 -rat 2 -db 1 || matrix -dp -ur -dim 1 -ib 4 -ob 10 -rat 4 -db 1 || matrix -dp -ur -dim 2 -ib 2 -ob 3 || matrix -dp -ur -dim 2 -ib 3 -ob 4 -rat 2 -db 0 || matrix -dp -ur -dim 3 -ib 1 -ob 3 || matrix -dp -ur -dim 3 -ib 2 -ob 3 || matrix -dp -ur -dim 3 -ib 2 -ob 3 -rat 2 -db 0 || matrix -dp -ur -dim 4 -ib 1 -ob 2 || lpo -ur -af || (arctic -dp -ur -dim 1 -ib 4 -ob 3[25] | arctic -dp -ur -dim 2 -ib 2 -ob 2[28] | arctic -dp -ur -dim 3 -ib 1 -ob 1[28] | arctic -dp -ur -dim 4 -ib 1 -ob 1[28] | fail) || (arctic -bz -dp -ur -dim 1 -ib 4 -ob 3[25] | arctic -bz -dp -ur -dim 2 -ib 2 -ob 2[28] | arctic -bz -dp -ur -dim 3 -ib 1 -ob 1[28] | arctic -bz -dp -ur -dim 4 -ib 1 -ob 1[28] | fail) || fail) } restore) )*[29])) || (bounds -cert || fail;(bounds -rfc -qc))))! || (( unfold || fail)*[7])!)[299])))</strategy></tool></proofOrigin></origin></certificationProblem>