• zea
    link
    fedilink
    arrow-up
    8
    ·
    4 months ago

    The color wheel, for instance

    • sushibowl@feddit.nl
      link
      fedilink
      arrow-up
      2
      ·
      4 months ago

      A colour wheel is not even partially ordered, I don’t think. There is a relation between some colours on the wheel but it’s not an ordering.

      • zea
        link
        fedilink
        arrow-up
        4
        ·
        4 months ago

        You can impose a partial ordering on it. HSL uses a hue angle. If we assume full saturation and lightness and pick an arbitrary direction to be positive, there’s your partial ordering. But not total ordering, there is no most clockwise color.

        • sushibowl@feddit.nl
          link
          fedilink
          arrow-up
          3
          ·
          4 months ago

          I feel like this doesn’t qualify as an ordering relationship, because of the circular nature of the wheel: for any two elements a and b (a ≠ b) on the wheel it’s both true that a is further clockwise than b and b is further clockwise than a (just keep rotating). This violates the antisymmetry property that an ordering relation should have.

          You can fix it by establishing some point on the wheel as “least clockwise” (essentially unfolding it into just a straight line) but that immediately establishes a total ordering.

          • zea
            link
            fedilink
            arrow-up
            1
            ·
            4 months ago

            Measure acute only. Idk how to deal with 180° though