I am in the process of writing a tag wiki for a tag over on physics. Because that particular concept is also relevant to Chemistry, an identical tag exists here. I anticipate that the excerpts will ultimately diverge from each other to include information relevant to the two fields. But for my initial seeding of the wikis, is it generally acceptable to simply copy and paste the same text?
As the putative copyright holder, I wouldn't object to someone else copying the text over to a tag wiki for another SE site. And my understanding is that by writing the one tag wiki, I am granting a license to SE that explicitly allows it to be copied to another tag wiki. Is this correct?