<ld:section>Logical structure of the contribution</ld:section>
<ld:body>The source files are grouped in planes and components
according to the following table.
- The notation for the relation or function introduced in each file
+ The notation for the relations or functions introduced in each file
is shown in parentheses.
</ld:body>
<ld:table name="ld_basic_2_src"/>