What you are looking for is a way to verify the authenticity of a document as well as make it alteration proof in a way that nobody can stake claim on it.

Inscribing on blockchain is overkill. Have you looked at other technologies than blockchain which are dedicated for this purpose.

There is almost nothing that can't be forged today. The attribution of documents for claiming originality of an idea has always been a tricky issue but most people, even the scientific community don't really care all that much about it. The final claim generally goes to whoever becomes popular first, rather than who comes up with the idea in the first place.

Why do you think would someone want this problem solved?