• Brainsploosh@lemmy.world
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    3 days ago

    They’re about as imaginary as numbers are in general.

    Complex numbers have real application in harmonics like electronics, acoustics, structural dynamics, damping, regulating systems, optronics, lasers, interferometry, etc.

    In all the above it’s used to express relative phase, depending on your need for precision you can see it as a time component. And time is definitely a direction.

    • Kogasa@programming.dev
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      2 days ago

      That’s not relevant to what they said, which is that distances can’t be imaginary. They’re correct. A metric takes nonnegative real values by definition

      • Brainsploosh@lemmy.world
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        2 days ago

        Why can’t a complex number be described in a Banach-Tarsky space?

        In such a case the difference between any two complex numbers would be a distance. And sure, formally a distance would need be a scalar, but for most practical use anyone would understand a vector as a distance with a direction.

        • Kogasa@programming.dev
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          2 days ago

          The distance between two complex numbers is the modulus or their difference, a real number