Small documentation issue

Tim,

Just a small documentation issue.

This line appears to be duplicated in the PDF:

"Permutation is a domain which can be used to compute permutations. It
is also an implementation of Group category."

In books/bookvol10.3.pamphlet its at line 145509.

I assume you would prefer me to let you know about this by email, like 
this, rather than cloning github and sending you a pull request?

One other thing:

Some of the diagrams have been expanded making them look blocky. the 
original diagrams are in scalable (.svg) form so its easy to export 
them, at other sizes, to .png or .gif (not .eps). However I think the 
document would be more readable if the diagrams were not larger than 
necessary. To my eye, a lot of skipping over big diagrams makes reading 
harder (it would be even better if text flowed around diagrams). This is 
a very minor thought and not worth spending much time on.

More generally, on the topic of documentation. It would be possible to 
write a lot more about the group theory around these domains. For 
instance, explanations of concepts like 'generators' and so on. The 
information added here was intended to be the aspects that are not 
easily found in maths textbooks. I do agree with some of your earlier 
posts that you made about the potential benefit that Axiom could bring 
to mathematics education, just the discipline it brings to having a 
consistent notation across the whole subject seems enormously valuable 
to me. However cramming an explanation of the whole of mathematics into 
bookvol10.3.pamphlet seems a bit over ambitious to me so perhaps its 
best not to try to explain everything?

Martin