amp;#8855;" -- circled times = vector product,
                                     U+2297 ISOamsb --&gt;
&lt;!ENTITY perp     CDATA "&amp;#8869;" -- up tack = orthogonal to = perpendicular,
                                     U+22A5 ISOtech --&gt;
&lt;!ENTITY sdot     CDATA "&amp;#8901;" -- dot operator, U+22C5 ISOamsb --&gt;
&lt;!-- dot operator is NOT the same character as U+00B7 middle dot --&gt;

&lt;!-- Miscellaneous Technical --&gt;
&lt;!ENTITY lceil    CDATA "&amp;#8968;" -- left ceiling = apl upst