FIRST LAW OF THE REACHABLE NOWS: No alternate versions of a person may be in eye-line of each other within the same now, or both will suffer immediate death by fire.
My novella “Hearts and Tails” in Spoon Knife 4: Spacetime is set in a soft-SF multiverse where WWI never ended, it just kind of petered out into a devastated landscape and a chemical-weapons cold war. There are 90’s tropes galore: magic, bio-engineered mutant powers, impossible psi-ops, and neon-glow cyberspace–depending which of four reachable nows one falls into. And maths. There are maths!!!
Okay, so I really love mathematics. I know this is mostly an unpopular opinion–Or not! Maybe you may share my love!
Macintosh Carroll, the central character of these stories shares my love. He is a maths savant with color-number synaesthesia.
a place where four four-dimensional world-lines line up creating a single now, a point shared by four spaces, four-D space-time four four four four times four sixteen blue blue blue blue like the bluest blue that ever was–
Mac stops writing and closes his eyes, the numbers washing him like seas. They are beautiful to him, beautiful and terrifying.
Mathematics–loosely, softly anyway–is how I keep the multiverse of the stories self-consistent and believable.
A formal system in mathematics is an engine for creating truths. It consists of axioms (accepted truths), rules (specified behaviors), and theorems (less obvious truths). New truths can be created by applying rules to axioms and/or theorems, so from a little bit of logic whole universes are made. Logical consistency is what builds a formal system, no matter how outlandish its axioms.
In the case of the Mac Carroll Multiverse, there’s a space-time phenomenon that lines up four realities at a single point. Some individuals can slip between the realities at that point. The axioms include the dynamics of the slip, many of the facts of our world circa 1991, plus unique world-facts such the Ottoman Empire dropping a chemical bomb on Germany because, after 40 years, they want out of the Axis. The rules are called The Laws of the Reachable Nows, and are recorded in a book shared by multiverse travelers. From those axioms and rules, the rest of the mulitverse follows.
But because I love disrupting stereotypes as much as I love maths, Mac’s also a shifty low-life punk with a belligerent attitude who is embarrassed by just how deeply he loves maths, and hides it behind a lot of attitude. Cuz nerdiness is punk rock too <3