Example:
expressions:

{host:key1.last()}

|

{host:key2.last()}

{host:key1.last()}

&

{host:key2.last()}

values:

{host:key1.last()}

= 2.55

{host:key2.last()}

= 5
result:
2.55 | 5 = PROBLEM; 2.55 & 5 = PROBLEM, but trigger remains in state OK