What does the hyphen mean in chkconfig run level in an /etc/init.d script?

I just have a simple question but scouring the search engines I have not found any explanation of what the - (hyphen) in the chkconfig runlevel actually stands for within the init script file. For example in /etc/init.d/mysqld the first few lines are like this: #!/bin/bash # # mysqld This shell script takes care of starting and stopping # the MySQL subsystem (mysqld). # # chkconfig: - 64 36 If anyone could provide me a link explaining this that would be awesome.