Just a note on the comments: as written below, you can use some HTML to format your posts. However, on this blog we can also use some LaTeX commands to typeset mathematics.

For an overview of LaTeX mathematics notation, look to one of the following references: 1, 2, and any others you find online.

For example,

\[ u_t-(u^m)_{xx} +b u^\beta=0\]

produces

\[ u_t-(u^m)_{xx} +b u^\beta=0\]