[R-SIG-Mac] What are the modifier keys for "Hide Others"

[Douglas Bates]

Sorry to keep asking dumb questions about using OS X but I have not
been able to decide what the combination of shortcut keys for the
"Hide Others" GUI selection is.  I know that "Hide Application" is
Apple-H but I don't know what modifier key is represented by that
backwards 7 symbol that is to be chorded with Apple-H for "Hide
Others".