& lt= = & gt& lty,x & gt∈R .S
& lt= = & gt& lty,z & gt∈R∧& lt; z.x & gt∈S
& lt= = & gt& ltx,z & gt∈s^(- 1)∧<; z,y & gt∈R^(- 1)
& lt= = & gt& ltx,y & gt∈S^(- 1)。 R^(- 1)
(2) Right? & ltx,y & gt∈(R^(- 1))^(- 1)
& lt= = & gt& lty,x & gt∈R^(- 1)
& lt= = & gt& ltx,y & gt∈R
If you don't understand, please ask. If it helps, please adopt it. Thank you!