The operator "<operator>" is not defined

This error occurs when the operation chosen is wrong or it can't be applied to the specified types.

Q: 3 + "four"
E: The operator "plus" is not defined.

You also receive this message if you use a word that the Relevance interpreter does not recognize. Here are some examples:

Q: Exists executable "file_name.exe" of system folder
E: The operator "executable" is not defined.

Here the word ‘executable’ is not a valid command in the relevance language.

The error is also generated when a non-existent property is queried:

Q: Version of key "HLKM/Software" of registry
E: The operator "version" is not defined.

Here, even though the relevance language knows the word ‘version’, it does not recognize it as a valid property of registry key, and therefore generates this error.