[Curmudgeon]

The posts in this thread give the spells that constitute the prerequisite counts in the Spell Table Appendix of GURPS Magic, pp.223-237.

Each prerequisite count is peculiar to that particular spell, or in other words, the prerequisite count is not concerned with how or why a spell ended up in the prerequisite count, only with whether you have to put a point into that spell before you can learn this spell. The prerequisite counts always assume the fewest possible spells to be the case. If a spell has a spell or an advantage as prerequisites, it assumes that the advantage is present. E.g., Beast-Soother (Magic p. 224 of the table) lists Persuasion, a spell, or Animal Empathy, an Advantage, as prerequisites and gives a prerequisite count of 0.

Alternate Prerequisites (Magic p.200) notes that the prerequisite counts given in the table do not account for non-spell prerequisites and suggests adding 1 to the count for every 10 character points of required traits.

The spells I give as making up the prerequisite count fall into one of two different categories. Those simply listed by name are specifically required as prerequisites and another spell cannot substitute for it. Those listed as by name followed by parentheses have more flexible parameters (whether that be a different spell of the same College or a spell from a different College entirely) and could have a different spell substitute for it while still meeting the count prerequisites.