Talk:Factor-critical graph

What is single graph?
A graph is also factor-critical if and only if it can be reduced to a single graph ...

What is single graph there? As I understand any graph is single, if we do not talk about two, three, four ... graphs. Jumpow (talk) 21:30, 15 May 2017 (UTC)
 * Typo for "single vertex". Fixed now. Thanks for catching this. —David Eppstein (talk) 04:38, 16 May 2017 (UTC)

is (a,b)-factor-critical
...is (a,b)-factor-critical...

Strange definition - a and b are never used. Jumpow (talk) 10:10, 16 May 2017 (UTC)