"Huh?"

So I'm reading this Greg Egan book, and this section of the book is Tenet, it's just Tenet, except he worked out all the math for how physics would work in a universe where the Einstein metric tensor was such as to make Tenet possible, and there's a full treatment of entropy

Also Egan wrote this book in 2013, so to be clear Egan did not get the *idea* from Tenet, unless Greg Egan himself is moving backward through time, presumably due to the corolois effect (he's Australian). That's how it works right? You flush the toilet & water rushes up into it?

Anyway one big break from Tenet in the Greg Egan version of the story is Egan's version respects CPT symmetry, which is to say, if you time-reverse matter you generally have to convert it to antimatter. So the first time anything flips in Tenet it should explode, destroying Earth

The way Egan works around this in his version of the story is by contriving (through topological means) a scenario where the heroes find an entire planet that was made out of antimatter to begin with, so it's safe to walk on it while time-reversed

(Note, there's one other option, the P in CPT symmetry, which is you could remain normal matter while time reversing IF you mirror your body left-right. But then you couldn't digest any food, due to protein handedness. I haven't seen Tenet and don't know if Nolan thought of this)

Okay now this is just starting to get suspicious. The implication here is Greg Egan sees Tenet in 2020, steals the idea and starts writing a book which he publishes in 2013; Rudy Rucker sees this, gets angry & eventually calls him out w/this story in 2009 https://twitter.com/ianbobmorris/status/1380062479833735171?s=19

After saying all this I should probably note the book in question is "The Arrows of Time"; it's the third book in the "Orthogonal" trilogy, so you'll want to read the other two books first, unless you (for obvious reasons) decide to read the series backward