Example 10.2 p 332

Cyclic forms of r90 and r270 are wrong.
r90 should be (1 7 9 3) (2 4 8 6) in the text of Example 10.2 and in  
Figure 10.4.
r270 should be (1 3 9 7) (2 6 8 4) in Figure 10.4.


Section 10.1.2 p 337

line 13: ... G_i = G_{i-1} ...
This is incorrect.  It should be (G_{i-1})_{i-1}.  I.e. the  
stabiliser of point i-1 in subgroup G_{i-1}.    Unfortunately this  
also illustrates an abuse of notation, in that the subscript is used  
both to indicate stabilising of a point AND for an element of the  
stabiliser chain.