The "is" in that sentence still isn't fully symmetric, I'd rather call it reversible. There is a learned relationship that "is composer of" has the same meaning as "composed" (as in "<Name> composed <Album>"). Now you can turn the active verb passive to switch subject and object: <Album> was composed by <Name>.
The final puzzle piece is then recognizing the difference between the question "Who composed <x>" and "Who did <x> compose", one asking for the object of the passive sentence and one for the object of the active sentence.
In a "traditional" system without ML you would represent this with a directional knowledge graph <Artist> --composed--> <Album>, with the system then able to form sentences or answer questions in either arrow direction. But that conversion is generally tricky unless you know how many other arrows exist. That's obvious with categories, but even if you know that one person composed a song that doesn't tell you that only that person composed that song. That can lead to unsatisfying answers, and might be a reason why this is hard for LLMs.
The final puzzle piece is then recognizing the difference between the question "Who composed <x>" and "Who did <x> compose", one asking for the object of the passive sentence and one for the object of the active sentence.
In a "traditional" system without ML you would represent this with a directional knowledge graph <Artist> --composed--> <Album>, with the system then able to form sentences or answer questions in either arrow direction. But that conversion is generally tricky unless you know how many other arrows exist. That's obvious with categories, but even if you know that one person composed a song that doesn't tell you that only that person composed that song. That can lead to unsatisfying answers, and might be a reason why this is hard for LLMs.