Why does everybody write (for example) INTp instead of INTP.
There is no difference between rationality in MBTI and Socionics.
It's just an invention of Ganin, as a respons to people who said that you have to switch J and P. This was a poor respons, but everybody seems to follow him blindly.
It would actually make more sense to write iNTP because introversion/extraversion differs more than rational/irrational between MBTI and Socionics.
I say, stop with the lower caps.