Could you repeat that? I didn't quite catch it.
Do you mean that <section> is structural, but <theorem>, <proof>,
<implies>, <xor> are semantic? Or are only the last two symbol place-
holders semantic?
What if <Section> is a place-holder which might start a section,
might start a chapter, but possibly does nothing at all? Or possibly
starts a section and at the same time creates a table of contents
entry, opens a solution file for problems in the section, displays a
message on the terminal and some other things? Is that semantic or
structural?
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%% Dr M J Piff, School of Mathematics and Statistics, University of %%
%% Sheffield, UK. +44 114 282 4431 e-mail: M.Piff@sheffield.ac.uk %%
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