Fix typos

diff --git a/include/deal.II/particles/particle_handler.h b/include/deal.II/particles/particle_handler.h
index fb9f6a45450e06e693e3af8d52a57efb3cd3a63b..267dfe30af791cbd80ecdecc3f93018b757d268b 100644 (file)
--- a/include/deal.II/particles/particle_handler.h
+++ b/include/deal.II/particles/particle_handler.h
@@ -205,10 +205,10 @@ namespace Particles
      * @note While this function is used in step-19, it is not an efficient
      *   function to use if the number of particles is large. That is because
      *   to find the particles that are located in one cell costs
-     *   ${\cal O)(\log N)$ where $N$ is the number of overall particles. Since
+     *   ${\cal O}(\log N)$ where $N$ is the number of overall particles. Since
      *   you will likely do this for every cell, and assuming that the number
      *   of particles and the number of cells are roughly proportional,
-     *   you end up with an ${\cal O)(N \log N)$ algorithm. A better approach
+     *   you end up with an ${\cal O}(N \log N)$ algorithm. A better approach
      *   is to use the fact that internally, particles are arranged in the
      *   order of the active cells they are in. In other words, if you iterate
      *   over all particles, you will encounter them in the same order as
@@ -217,7 +217,7 @@ namespace Particles
      *   to the next cell, you increment the particle iterator as well until
      *   you find a particle located on that next cell. Counting how many
      *   steps this took will then give you the number you are looking for,
-     *   at a cost of ${\cal O)(\log N)$ when accumulated over all cells.
+     *   at a cost of ${\cal O}(\log N)$ when accumulated over all cells.
      *   This is the approach used in step-70, for example. The approach is
      *   also detailed in the "Possibilities for extensions section"
      *   of step-19.
@@ -238,10 +238,10 @@ namespace Particles
      * @note While this function is used in step-19, it is not an efficient
      *   function to use if the number of particles is large. That is because
      *   to find the particles that are located in one cell costs
-     *   ${\cal O)(\log N)$ where $N$ is the number of overall particles. Since
+     *   ${\cal O}(\log N)$ where $N$ is the number of overall particles. Since
      *   you will likely do this for every cell, and assuming that the number
      *   of particles and the number of cells are roughly proportional,
-     *   you end up with an ${\cal O)(N \log N)$ algorithm. A better approach
+     *   you end up with an ${\cal O}(N \log N)$ algorithm. A better approach
      *   is to use the fact that internally, particles are arranged in the
      *   order of the active cells they are in. In other words, if you iterate
      *   over all particles, you will encounter them in the same order as
@@ -250,7 +250,7 @@ namespace Particles
      *   to the next cell, you increment the particle iterator as well until
      *   you find a particle located on that next cell. This is the approach
      *   used in step-70, for example, and has an overall cost of
-     *   ${\cal O)(\log N)$ when accumulated over all cells. The approach is
+     *   ${\cal O}(\log N)$ when accumulated over all cells. The approach is
      *   also detailed in the "Possibilities for extensions section"
      *   of step-19.
      */
@@ -269,10 +269,10 @@ namespace Particles
      * @note While this function is used in step-19, it is not an efficient
      *   function to use if the number of particles is large. That is because
      *   to find the particles that are located in one cell costs
-     *   ${\cal O)(\log N)$ where $N$ is the number of overall particles. Since
+     *   ${\cal O}(\log N)$ where $N$ is the number of overall particles. Since
      *   you will likely do this for every cell, and assuming that the number
      *   of particles and the number of cells are roughly proportional,
-     *   you end up with an ${\cal O)(N \log N)$ algorithm. A better approach
+     *   you end up with an ${\cal O}(N \log N)$ algorithm. A better approach
      *   is to use the fact that internally, particles are arranged in the
      *   order of the active cells they are in. In other words, if you iterate
      *   over all particles, you will encounter them in the same order as
@@ -281,7 +281,7 @@ namespace Particles
      *   to the next cell, you increment the particle iterator as well until
      *   you find a particle located on that next cell. This is the approach
      *   used in step-70, for example, and has an overall cost of
-     *   ${\cal O)(\log N)$ when accumulated over all cells. The approach is
+     *   ${\cal O}(\log N)$ when accumulated over all cells. The approach is
      *   also detailed in the "Possibilities for extensions section"
      *   of step-19.
      */