theorem letr (a b c: nat): $ a <= b -> b <= c -> a <= c $;
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | anl | a <= b /\ b <= c -> a <= b |
|
2 | anr | a <= b /\ b <= c -> b <= c |
|
3 | 1, 2 | letrd | a <= b /\ b <= c -> a <= c |
4 | 3 | exp | a <= b -> b <= c -> a <= c |