Each letter in the infinitive is tagged with the particular alternation pattern the verb exhibits for that infinitive letter, or with 0 if the verb exhibits no alternation in that letter during conjugation.
the verb a tresȃlta (to quiver) is labelled as follows: t r e sȃ l t a 0 0 0 0 a 1 0 t 0 T 1 Here, T 1 encodes the ending pattern received by the class of verbs to which a tresȃlta belongs, as presented in Table 3 along with a few other ending patterns.