Description: The "less than or equal to" relation in the extended real numbers. (Contributed by Thierry Arnoux, 14-Mar-2018)
Ref | Expression | ||
---|---|---|---|
Assertion | xrge0le | |- <_ = ( le ` ( RR*s |`s ( 0 [,] +oo ) ) ) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | ovex | |- ( 0 [,] +oo ) e. _V |
|
2 | eqid | |- ( RR*s |`s ( 0 [,] +oo ) ) = ( RR*s |`s ( 0 [,] +oo ) ) |
|
3 | xrsle | |- <_ = ( le ` RR*s ) |
|
4 | 2 3 | ressle | |- ( ( 0 [,] +oo ) e. _V -> <_ = ( le ` ( RR*s |`s ( 0 [,] +oo ) ) ) ) |
5 | 1 4 | ax-mp | |- <_ = ( le ` ( RR*s |`s ( 0 [,] +oo ) ) ) |