Reading through Jean-Eric Pin's "Mathematical Foundations of Automata Theory". Love this book. However, I am confused by the following section, and am hoping for some clarity and more examples if possible. I need this for my research. [Syntactic order definition][1] I am not sure exactly how it is used to create the syntactic order in the following example: [Example][2] Putting the above example into this automaton: - $Q = \{1,2,3\}$ - $I = \{1\}$ - $F = \{3\}$ - $A = \{a,b\}$ - $E = \{(1,a,2),(2,a,2),(2,b,3),(3,b,3),(3,a,2)\}$ For the above statements $u \le v $ and $s, t \in A*$, $$ sut \in L \implies svt \in L $$ Would this look like the following from the example above? $(1,a,2) \implies (1,aa,2)$ Does this define the relations from the example above? That is, are the relations from the example above (i.e. '$aa = a$', etc.) syntactic congruence? And, how are they used to define the syntactic order? [1]: https://i.sstatic.net/68Z3G.jpg [2]: https://i.sstatic.net/iMV15.jpg