| page | line | correction or comment |
| 32 | --8 | $x ^ \dagger$ should read $c ^ \dagger$ |
| 133 | 16 | $Hom(R,B) / Hom(F,B)$ should read $Hom(R,B) / im Hom(F,B)$ |
| --4 | $_[p,q]$ should read $_(p,q)$ $[ , ]$ should read $( , )$ "least common multiple" should read "greatest common divisor" |
|
| 233 | --13 | The dual numbers are originally due to Clifford. |