[STATEMENT]
lemma "catMaybes\<cdot>(map\<cdot>f\<cdot>x) = mapMaybe\<cdot>f\<cdot>x"
[PROOF STATE]
proof (prove)
goal (1 subgoal):
 1. catMaybes\<cdot>(map\<cdot>f\<cdot>x) = mapMaybe\<cdot>f\<cdot>x
[PROOF STEP]
by auto