-Let \(i:\mathord {\textnormal {\textsf {Level}}}\).
Then \(i\le i\).
-Let \(i_{1},i_{2},i_{3}:\mathord {\textnormal {\textsf {Level}}}\)
and suppose that \(i_{1}\le i_{2}\)
and that \(i_{2}\le i_{3}\).
Then \(i_{1}\le i_{3}\).
-Let \(i_{1},i_{2}:\mathord {\textnormal {\textsf {Level}}}\)
and suppose that \(i_{1}\le i_{2}\)
and that \(i_{2}\le i_{1}\).
Then \(i_{1}\equiv i_{2}\).
-Let \(i:\mathord {\textnormal {\textsf {Level}}}\).
Then \(0\le i\).