misprints in chapter 'Vectors and Matrices'

[Brian Gough]

Mario Pernici writes:
 > Dear Sirs,
 >  in the chapter 'Vectors and Matrices'
 > 
 > < Matrix operations
 > < The following operations are only defined for real matrices.
 >   Eliminate this line; they are defined also for complex matrices.
 > 
 > 
 > < Finding maximum and minimum elements of matrices
 >   Add: The following operations are only defined for real matrices.
 > 

Thanks. Now updated.