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<p>Dear all,</p>
<p>Guillermo González Campos and I are garnishing our (future)
Cabecar grammar with formulas of syntactic structure. Each
representation layer (like "structural", "semantic", ...) is
one-dimensional. The structural layer involves symbols
representing significative components plus indexed brackets. Some
constructions comprise a component <font color="#990000">C</font>
which is obligatory, but may occur in different positions.
Sometimes a "basic" position may be identified, of which other
positions are optional permutations. If so, I can provide a
formula for the basic position and add a prose sentence on the
variation. Now suppose there is no such basic position. A
possibility of representing such a state of affairs is to provide
a construction formula for each of the variants, like:</p>
<p>X <font color="#990000">C</font> Y</p>
<p>X Y <font color="#990000">C</font></p>
<p>Rather space-consuming and less than elegant. Is there a notation
which allows one to write something like</p>
<p>X <font color="#990000">C</font> Y <font color="#990000">C</font></p>
<p>to mean that <font color="#990000">C</font> can and must occupy
either of the two positions? (Ordinary parentheses would not work,
in my view, as they imply optionality.)<br>
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<p>Thanks for advice,</p>
<p>Christian<br>
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<div class="moz-signature">-- <br>
<p style="font-size:90%">Prof. em. Dr. Christian Lehmann<br>
Rudolfstr. 4<br>
99092 Erfurt<br>
<span style="font-variant:small-caps">Deutschland</span></p>
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<td>Tel.:</td>
<td>+49/361/2113417</td>
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<td>E-Post:</td>
<td><a class="moz-txt-link-abbreviated" href="mailto:christianw_lehmann@arcor.de">christianw_lehmann@arcor.de</a></td>
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<td>Web:</td>
<td><a class="moz-txt-link-freetext" href="https://www.christianlehmann.eu">https://www.christianlehmann.eu</a></td>
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