A common point of confusion when going from MBTI to socionics, is the type acronyms. Why not just use the same name for them? But even when socionics and MBTI does use the same name, such as INTp and INTP, it means two different things.
In Carl Jung’s work, he described three different aspects of a type. Extraversion and introversion, which he gave the most attention. Only after the attitude comes the functions. Two irrational (those would be the perceiving functions in MBTI, S and N) and two rational (judging functions, T and F) functions. When Isabel Myers and Katherine Briggs created MBTI, they invented a four letter acronym for a type, rather than saying “introverted thinker with auxiliary intuition”, they used INTP. The P in their system is based on the first extraverted function. So for an introvert, this would be their auxiliary.
But when the four letter acronym was introduced to socionics, it took a different route. Instead of describing the first extraverted function, the last letter, J or P, pointed to the dominant function of the type. Not the first extraverted, but the first function overall. The attitude of the entire type. This works well with the extraverts, since they would share the same acronym in both MBTI and the four letter version of socionics. For introverts though, it’s more confusing. A type with leading Ti and auxiliary Ne would be an INTP in MBTI, the P pointing at the auxiliary Ne, whereas they in socionics would be called INTj, with the J pointing to a rational type (one that leads with a rational function).
However, in socionics, there are two other type of type acronyms. The first one is a three letter acronym. The first of those three letters stands for the dominant function, the second for the auxiliary (or creative) function, and the third letter stands for whether the type is introverted or extraverted. It doesn’t use T and F though, but L (logic) instead of thinking, and E (ethics) instead of feeling. Following this system, someone with leading Ti and creative Ne would be called LII. Logic, intuitition, introversion. Someone that leads with Fe, with creative Si, would be called ESE. Ethics, sensing, extravsion.
The third way to name them comes from a tradition of using other names for the functions themselves. Instead of calling them Fe or Si, they are replaced by a single letter, the first in a word that describes them. The type name would be the two primary functions of the type, in order. Those letters can also be replaced by symbols, as you can see below.
Se – Force (F) –
Si – Senses/sensation (S) –
Te – Pragmatism (P) –
Ti – Laws (L) –
Ne – Ideas (I) –
Ni – Time (T) –
Fe – Emotions (E) –
Fi – Relations (R) –
Using this method, an INTP would either be called LI or .