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That's perfectly fine, and sometimes done in expository writing.

https://www.amazon.com/Algebraic-Geometry-Projective-Varieti...

This get's very tedious to write if you use this over and over in proofs.

If you had to tediously write it over and over in proofs, why can't just you give it a name or an abstraction?

↑ As you would do in programming.

The reason I found is because in math adjacency is interpreted as multiplication. There is no mandatory separator character.

See my comment here: https://news.ycombinator.com/item?id=25207527

Proofs can be very long, writing out full pages with single letters let alone full words would be difficult to parse

Source code for software is much, much, much longer and structured in directories and version controlled and automatically syntax checked and automatically tested and even edited simultaneously remotely across the globe.

And in case of some languages we can even use the full Unicode for variable names (Julia). The only restriction is we have mandatory separators and adjacency does not automatically mean multiplication.

See for example VS Code Live Share for the last one if you are not aware of it.