Contextualized ComplexFacts

Placeholder for a discussion of the final puzzle piece for v0.8: contextualized complex facts, where our changes to ComplexFacts and our addition of "FrameMappings" come together.

I posted an overview of thoughts so far as comment.

For now, I would be happy for v0.8 to just decide on something that can support all known real-world examples, even if we cannot fully settle all the theoretical debates yet. One suggestion for this is in !26 (merged) , but if you think this is not the right direction we can also discuss here.