# Small typo in "An Algorithm for the Construction of Intrinsic..."

## Alec Jacobson

## July 11, 2014

Upon implementing the Intrinsic Delaunay Laplacian according the helpful notes in "An Algorithm for the Construction of Intrinsic Delaunay Triangulations with Applications to Digital Geometry Processing" [Fisher et al 2006], I noticed a small typo. Specifically I’m following this version of the document. The issue is regarding the computation of the length of the "flipped edge" f. Currently the last step in section 2.2 uses the Law of Cosines, writing that:

```
f = sqrt(b^2 + c^2 - 2 cos(alpha + delta))
```

This should be:

```
f = sqrt(b^2 + c^2 - 2 b c cos(alpha + delta))
```