Front matter

Conventions are those of XVI-K.tex (quoted there from XVI-J.tex and XII-C.tex). Indices are moved with $\eta$; parentheses in index expressions include the factor $\frac{1}{2}$. Multi-indices $a,b,p,q,\gamma \in {\mathbb{N}}^4$ act by ${\partial }^a={{\partial }_0}^{a_0}\cdots {{\partial }_3}^{a_3}$, $|a|=a_0+\cdots +a_3$. The symmetric basis is $B_0,\dots ,B_9$ in the order $(00),(01),(02),(03),(11),(12),(13),(22),(23),(33)$, $(B_{(ab)}{)}_{ab}=(B_{(ab)}{)}_{ba}=1$; for a symmetric tensor $X={\sum }_i{X}^i{B}_i$, $X^i=X_{ab}$ for $i=(ab)$ (XVI-K, Section K.1). Equation labels of predecessor files are cited as “file, label”.