[trenchgun]

F# inherits <> from ML, which inherits it from Algol, which invented it. But that was actually a bad idea, since it deviates from mathematical practice. To follow math, it would be better to use != as in C and those inspired by it, or /= as in Haskell. Or maybe even =/= if you really want to go for the mathy looking notation.

Elixir uses <> as an operator for concatenation of binaries, (which does form a monoid of course), not to be confused with how Haskell uses <> as a binary operator of a Monoid, but for sure inspired by it. And Gleam picked it up from them, probably, to use for a special case of a list monoid, String. And Haskell created <> for Monoid, because it would be too confusing to use multiplication sign for the binary operation like mathematicians do. It would not be ok in programming context.