# Least Action

Nontrivializing triviality..and vice versa.

## Errata for Basic Concepts of String Theory by Blumenhagen, Lüst and Theisen

This is an unofficial errata for the book Basic Concepts of String Theory by Ralph Blumenhagen, Dieter Lüst and Stefan Theisen. I couldn’t find an official errata, but I’ll probably discontinue this at some point when I do run into one.

Chapter 2: The Classical Bosonic String

• Page 8. The line below equation 2.3. There should be two dots, one each on $x^\mu$ and $x^\nu$ in the definition of $\dot{x}^2$.

Chapter 8: The Quantized Fermionic String

• Page 213: Equation 8.56. There is only one charge conjugation matrix in odd dimension d = 2n+1, either $C_+$ or $C_-$. To find out which one it is, for odd $d$, determine $d(d-1)/2$: if this is even, $C_+$ exists; if it is odd, $C_-$ exists. So, equation 8.56 is wrong: one should use $C_-$ for odd $n$, and $C_+$ for even $n$.To derive this criterion, compute $C \gamma_c C^{-1}$ and observe that it equals $(-1)^{d(d-1)/2} \gamma_c$ in general, which determines whether $C = C_+$ or $C = C_-$. For a quick list of charge conjugation matrices in various dimensions and their symmetry properties, see page 11 of http://www.nikhef.nl/~t45/ftip/AppendixE.pdf.

Chapter 14: String Compactifications

• Page 453: below equation 14.70. There’s an extra q after $\Lambda^q$.
• Page 454: Equation 14.76. There’s an extra $\wedge$ after $\bar{\partial}_j \omega_{i_1,\ldots i_p \bar{j}_1\ldots \bar{j}_p}$.
• Page 510: Equation 14.262. The $e^{e}$ on the right-hand side in the local Lorentz transformation of the vielbein should be $e^{b}$.

Chapter 18: String Dualities and M-Theory

• Page 690: The expression for $\tilde{F}^{(p+2)}$ in the paragraph below equation (18.26) has extra indices. It is the contraction of $\tilde{F}_{M_{0}\ldots M_{p+1}}$ with $\tilde{F}^{M_{0}\ldots M_{p+1}}$.