
| Page X.  "Chapter~2, omitting Section~2.5, can be regarded as a collection of examples.” should read "Chapter~2, omitting Section~2.6, can be regarded as a collection of examples.” | 
| 
                
                 Page 5. Exercise 1.1.1.  It is better to use Italic font style for denoting aardvark. | 
| 
                
                 Page 13. Example 1.4.1.  The sentence “HH and input the string aba Then” should read “HH and input the string aba, then” | 
| Page 39. Example 2.4.4.  The last sentence: "It is now easy to draw the transition table of the required automaton” Transition table should read transition diagram. | 
| Page 43. Proof of Proposition
                    2.5.5. "But this is equivalent to s0 ·x
                    ∈ F and t0 ·x ∈ G,” The word `and' should be be
                    emphasised. | 
| Page 71. Proof of Proposition
                    3.3.6. "the strings u_1, (a_1u_2), . .
                    . , (a_{n−1} u_n) is accepted by L(A)” should read "the strings u_1,
                    (a_1u_2), . . . , (a_{n−1} u_n) is accepted by A” | 
| Page 72.  The 4th equation of
                  Section 3.4. “L(A) = I \cdot A^* \cap T \neq
                  \emptyset” should read “L(A) = \{ w \in A^* \mid I
                  \cdot w \cap T \neq \emptyset \}" | 
| Page 89. Example 4.1.3. “We calculate $\A$ for the
                        $\id$-automaton of …” should read “We calculate
                        $\A^s$ for the $\id$-automaton of …” | 
| Page 92. The last sentence of
                    the proof of Theorem 4.2.1. “It is easy to check that
                    $L({\bf B}) = L$” should read “It is easy to check
                    that $L({\bf D}) = L$” | 
| Page 115. The second line. "where $b$ and $c$ are known”
                    should read "where $a$, $b$ and $c$ are known” | 
| Page 123 (middle). In the proof of
                  Theorem 5.4.9. "By using the ith row of the
                  equation X = CX + R,” should read "By using the ith
                  row of the equation X' = C’X' + R’," | 
| Page 133. Example 6.1.7. “given by the transition table
                    below:” should read “given by the transition diagram
                    below:” | 
| Page 135. In the proof of
                    Theorem 6.2.1-(1). "Finally, the set of terminal
                    states is defined to be $T$” should read 
                    "Finally, the set of terminal states is defined to
                    be $T = T_1 \cup T_2$” | 
| Page 137.  The definition
                    of $F(r)$. $F(r) = \{x \in A^{2} \colon \:
                    A^{\ast} \cap L(r) \neq \emptyset \}$ should read
                    $F(r) = \{x \in A^{2} \colon \: A^{\ast} x A^{\ast}
                    \cap L(r) \neq \emptyset \}$ | 
| Page 141, line 6. "As we shall
                    prove later in this section,’ should read  "As
                    we shall prove later in this chapter," | 
| Page 150, Theorem 7. Forgot a
                    fullstop in the statement. | 
| Page 155, in the proof of
                    Theorem 7.4.2. "Now B is reduced,” should read “Now
                    A and B are reduced,”   | 
| Page 163, Example 7.5.10, Item
                    (7). "By Proposition 7.5.4” should read “By
                    Proposition 7.5.3” | 
| Page 168, Summary of Chapter 7,
                    about minimal automata. “reduced and connected”
                    should read “reduced and accessible” | 
| Page 181, Algorithm 8.2.5. "By
                    construction, $| vw’ | < |w|$”. This is not true
                    because a relation can have words with same length.
                    “By construction, for the tree order $<$, $ vw’
                    < w $” is ok. | 
| Page 192, Example 9.1.2. Forgot
                    fullstop before “Here”. | 
| Page 201, Example 9.2.5.
                    "Proposition 9.2.4” should read “Theorem 9.2.4” | 
| Page 206, 1st line (Example
                    9.2.14).  There is missing notation here.
                    $\mathbb{Z}_{n}$ should be formally defined. | 
| Page 209, in the proof of
                    Theorem 9.4.1. “Then $ i \cdot (uxv) \in L $” should
                    read “Then $ i \cdot (uxv) \in T $" | 
| Page 214, Remarks on Chapter 9,
                    1st paragraph. The relation $\rho_\A$ is written as
                    $\rho$ twice. | 
| Page 218, proof of Theorem
                    10.1.2. "$i, i+1, \ldots i +
                      (k-1)$" -> "$i, i+1, \ldots, i + (k-1)$”
                    (forgot a comma before $i+(k-1)$). | 
| Page 222, 1st paragraph.
                    "$\pi_{1}, \pi_{2} \colon \: S \times T \rightarrow
                    S$” should read "$\pi_{1} \colon \: S \times T
                    \rightarrow S, \pi_{2} \colon \: S \times
                      T \rightarrow T$” | 
| Page
                      222, Example 10.1.9. “Let
                    $S_{1},S_{3},S_{3}$” should read “Let
                    $S_{1},S_{2},S_{3}$”. | 
| Page
                      230, proof of Proposition 10.2.11. "be
                    monoid homomorphisms such that and $L_{1} =
                    \alpha_{1}^{-1}(P_{1})$ and $L_{2} =
                    \alpha_{2}^{-1}(P_{2})$.”should read “be monoid
                    homomorphisms such that $L_{1} =
                      \alpha_{1}^{-1}(P_{1})$ and $L_{2} =
                      \alpha_{2}^{-1}(P_{2})$ holds for some
                    subsets \(P_{1} \subseteq M_{1}\) and \(P_{2}
                    \subseteq M_{2}\)." | 
| Page
                      253, proof of Theorem 11.4.2. "If $r = s'$ then
                      $L(s)$ recognises $s'$ by Proposition~10.2.8(i);  in fact, in this case
                      $L(s)$ is also the syntactic monoid of $s’$.” should
                        read "If $r = s'$ then $M$ recognises $L(s’)$ by
                        Proposition~10.2.8(i);”  in
                      fact, in this case $M$ is also
                    the syntactic monoid of $L(s’)$." | 
| Page
                      257, proof of Proposition 11.4.9, the last
                      sentence. "Thus $\phi (u) = n \phi(a)$,
                    where $n \phi(a)M = mM$. Thus $n = \phi (w) =
                    \phi(u)\phi(v) = n \phi(a)\phi(v) \in mM$.”
                    should read “Thus $\phi (u) = n' \phi(a)$, where $n'
                    \phi(a)M = mM$ for some $n’ \in M$ and $a \in A$. Thus $n = \phi
                    (w) = \phi(u)\phi(v) = n' \phi(a)\phi(v) \in mM$.” | 
| Page 260, the last equation.
                    Forgotten a fullstop. | 
| Page 267, Examples 12.1.3-(4).
                    "The proof of (VM2) follows from Lemma~11.2.13,”
                    should read "The proof of (VM2) follows from
                    Lemma~11.2.5,”. | 
| Page 270, after proof of
                    Lemma 12.1.8. "The definition below is not an
                    obvious one, although it is partially motivated by
                    Lemma~12.1.7.” should read  "The
                    definition below is not an obvious one, although it
                    is partially motivated by Lemma~12.1.8.” | 
| Page 274, first sentence. "We
                    shall now describe a method for describing
                    pseudovarieties of semigroups.” should read "We
                    shall now describe a method for describing
                    pseudovarieties of monoids” (pseudovariety of
                    semigroups has not yet been defined). | 
| Page 274, before Example 12.2.3.
                    The notion “ultimately defined” has yet to have
                    been defined. Thus add the following sentence after
                    the definition of $\mathsf{M}’’$: “We say that
                    $\mathsf{M}''$ is {\em ultimately defined} by the
                    equations $(u_{n} = v_{n})_{n \geq 1}$.” | 
| Page 274, Example 12.2.3. “By
                    Theorem 10.3.2,” should read “By Theorem 11.3.2,” | 
| Page 275, proof of Theorem
                    12.2.4. "Put $A_{n} = \{a_{1}, \ldots a_{n} \}$.”
                    should read "Put $A_{n} = \{a_{1}, \ldots, a_{n}
                    \}$.”  | 
| Page 275, proof of Theorem
                      12.2.4, second paragraph. $A_n$ is written as $A$
                      twice. | 
| Page 276, Remarks on Chapter 12. "condition (VL1) is natural from
                    the point of view of the results we proved back in
                    Section~2.6;” should read "condition (VL1) is
                    natural from the point of view of the results we
                    proved back in Section~2.5;” |