Sentence 1: 桌子上有一本作业 Sentence 2: 桌子上有我的作业
I think both sentences are correct. However, I just watched a grammar video which mentioned the existential sentence with "有" can only carry a non-specific noun. If so, "桌子上有我的作业“ wouldn't be correct, because "我的作业" is specific. So I am confused. Can anyone explain this?