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A quick Chinese lesson (lemmy.world)
submitted 5 months ago by to c/memes@lemmy.world
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[–] 6 points 5 months ago (14 children)

Fun fact, for a long time in history minus (-1) did not exist

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  • [–] 8 points 5 months ago (5 children)

    In the history of mathematics, -1 was understood waaaay before 0.

    For the Greeks, doing 1-1 would be invalid, something close to dividing by zero for us.

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  • [–] 0 points 5 months ago (3 children)

    Dividing by zero is well understood and sometimes even well defined.

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  • [–] 4 points 5 months ago (2 children)

    That's a stretch.

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  • [–] 1 point 5 months ago (1 child)

    We know the limit of it and on a Riemann sphere it is defined as infinity.

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  • [–] 2 points 5 months ago

    We know the limit of a/x as x --> 0 if a ≠ 0.

    The limit is different if a = 0.

    The limit of the division function under certain conditions is not the same as division - division has a discontinuity at 0 which is expressing the same thing.

    Defining division by zero only works if you don't care to preserve the field axioms, which is often inconvenient and so not done. The Riemann sphere is not a field, and fairly niche in the context of mere division, so I stand by my accusation of this being misleading.

    The policy of not defining division by zero to preserve the cancellation law is the most sensible default.

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  • [–] 5 points 5 months ago (2 children)

    I saw a video years ago where somebody was talking (with a translator) to a tribe, I forget where. He asked how do they count. They would point with one hand to the other hand. Once they've got to five they start pointing to other parts of the arm moving upwards. He then asked what if you need to count higher. They looked confused, why would they need to count higher.

    For them they could exist without needing to count beyond teens.

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  • [–] 2 points 5 months ago* (1 child)

    I'm not sure how accurate that is, calenders are pretty important for being able to survive, and surely they need to figure "do we have enough food to last the rest of this season".

    Maybe they have different math for that or there was an issue with translation.

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  • [–] 1 point 5 months ago

    These dudes lived in the tropics and lived off the fat of the land. They didn't need to worry about seasons in the way more northern/southern hemisphere people do.

    Totally agree though. Maths, astrology, water sources, farming. All very important to sustain a civilisation.

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  • [–] 2 points 5 months ago* (last edited 5 months ago)

    Mathematics for much of human history was discrete - it had to be connected to something tangible which you can see, touch or feel. Negative numbers first arose in China, subsequently the use numerical operations on negative numbers and the conceptualization and use of zero arose in India. Spiritual concepts within dharmic philosophies such as Buddhism helped lead to these ideas.

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