 through time, and 
&gt; consider these a fundamentally different kind of entity than things 
&gt; which happen at a time? Do they assume that truths are asserted at a 
&gt; time (and hence are implicitly or explicitly tensed) or are the 
&gt; assertions themselves timeless, and asserted about temporally located 
&gt; things? 
     Certainly, axioms serving as assertions about specific material 
objects in space-time till be time-dependent, but axioms used for 
defining classes of concepts by their relation