To undefined and beyond...

OK, so maths have rebranded infinity as undefined. I think this gets us back to the essential difference between physics and maths - that physics is measurable. So in physics, we need to be clear that infinity will mean something different. In the case of infinite resistance, what we actually mean is that it is UNMEASURABLY BIG. Remember, maths like their perfect fractions like 2/7. That won't do in physics. We use decimal fractions to show the precision of the measurement. It DOES matter whether you write it down as 0.29, 0.286 or 0.2857. So there.