I used to be a maths teacher ...
I did not. In fact, I didn't even show up to the maths classes... But of course, that would explain some part of my misunderstanding. Another part would be the language, I guess. It is no secret that English by far is not my first language. Sometimes I think I have made myself very understable, only to realize I was not understood at all. No, I am not talking about my marriage! (I am a batchelor). Only today I tried this situation: I wrote the (French) author of RegSeeker and explained, no, read for yourself and tell me what you think I wrote:
I thank you for a very fine and free RegSeeker 1.55, and ask of you to make an (installed) upgrade version with Registry Indexing, in order to minimize search-time, please. I use RegSeeker several times a week and are waisting quite a lot of time just waiting.
The poor guy had no idea what I was talking about. Do you?
Anyway; this is not a guessing contest; I am merely pointing out that language can block bridges, and I often don't understand the maths nor the details of the language. But this time I guess it was Zinkernagel's sentence all alone: I didn't think hard enough, if at all...
[Edit: typos, etc]