Definition 13.3 ($t{p}^M$). Given $a_1,\dots ,a_n\in M$, let ${tp}^M(a_1,\dots ,a_n∕A)$ be the set of all $L_A$-formulas $\varphi (x_1,\dots ,x_n)$ such that $M\models \varphi (a_1,\dots ,a_n)$ (usually $a_i\notin A$).

${tp}^M(\overline{a}∕A)\in S_n^M(A)$ and $\overline{a}\models {tp}^M(\overline{a}∕A)$.