Under the Magic Skill Modifiers on page 59, it says, "The following magic skills are used in sorcery (see page 381) and are not commonly known to all adventurers: Combine/Separate, Dominate, Invoke, and Tap." (bold mine).
Page 381 has nothing on these. Page 383 says, "Six techniques are used in sorcery: Command, Combine, Separate, Summon, Dispel, and Tap. Similar to the sorcerous use of Runes, these techniques are not skills." (again, bold mine).
I assume Command was originally named Dominate, Summon was Invoke, and Dispel was only later added.