What does this CSS declaration mean?

could you tell me what does this declaration mean. Why 开发者_StackOverflow中文版does it have ul tag mentioned twice?

.jqueryslidemenu ul ul

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It would match all UL tags that are descendants of a UL Tag that is a descendant of an element that has the jqueryslidemenu class on it.

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<div class="jqueryslidemenu">
<ul>
<ul> --> it will be for this one