I generally take English sentences like that to be existential claims, rather than universal ones.<p>For example, if I was talking about an exciting new business plan to serve alcohol in a building and someone replied &quot;Bars already serve drinks.&quot;, you probably wouldn&#x27;t object saying that <i>some</i> bars don&#x27;t serve drinks - that&#x27;s not really the point.<p>I can probably concoct a counterexample, but given that most BSTs that one would actually use under that terminology are self-balancing ~O(log n) structures I am tempted to go with this. I imagine if &quot;self-balancing BST&quot; was used the objection might never have been raised, even though not strictly all self-balancing BSTs have all O(log n) operations.<p>Either way it&#x27;s a semantic thing that has little to do with what BST means (we agree on that) and more to do with interpreting the ambiguities of English.