・Corrected misprints in \S 3.3, (ii) ("As we shall we see" ---> "As we shall see"),
　(vi) ("is highly reminiscent of the well-known" ---> "highly reminiscent of the 
　well-known")

・Corrected misprints in \S 3.4, (i) ("algorthmic construction of a cyclotomic" --->
　"algorithmic construction of a cyclotomic"), (ii) ("group law in written additively"
　---> "group law is written additively"), (ii) ("by means of technique discussed" ---> 
　"by means of the technique discussed")

・Corrected a misprint \S 3.6, (i) ("symmetries of the consituent" ---> "symmetries of
　the constituent")

・Added a supplementary explanation following the second display of \S 4.1, (i)

・Added a supplementary explanation to the final portion of \S 4.2, (i)