Comparison operators behave unintuitively

Hi!

I noticed that comparison operators behave in a non-intuitive way. Here is an example:
```
a=setinterval(-1e-10,1e-10)
a>=0 # returns true
a<=0 # returns true
a==0 # returns false
a>0 # returns false
a<0  # returns false
```
I would guess that all these operations should return false, but for some reason $\leq$ and $\geq$ return true.  
