## Japanese for mathematics: Manifold

So, I’m trying to learn Japanese, being as I live in Japan, so I’ve decided to start this series.  I’m armed with a mathematical English-Japanese dictionary, a kanji look-up website, and a willingness to be corrected if I happen to have any Japanese readers.  So, this post may not appear correctly if you don’t have Japanese fonts installed, just a warning, and if I explain anything incorrectly, let me know in the comments and I’ll correct the post.

Our first word is “manifold.”  Every geometer of every stripe has studied manifolds at some point, and lots of other concepts require manifolds before they can even be defined, so that’s where we’re starting.

First, the individual kanji, with links to description pages: , , and .  We put these three together, and get “tayoutai” which means “manifold.”

The first of these kanji, 多, can be pronounced as “ta,” which seems to be the most common reading.  Looking at the actual structure of the kanji, this seems reasonable, as “ta” is written タ in katakana, and the kanji is two copies of this kana.  As for meaning, it means “many” or “much” or “frequent,” and is the beginning of a direct translation of manifold.

The second character, 樣, is apparently not a general use character, it only occurs in special situations.  Here, it is pronounced “you” (which we should note is two syllables “yo-u”) though can also be pronounced “sama.”  Here it seems to be being used to indicate will or “way of” in some sense.

And finally, we get to the last character: 体.  Here it is pronounced “tai” (again, ta-i), though it has others.  It means “body” or “object.”

So, altogether, “tayoutai” or 多様体 means something like “many ways object” or “diverse bodies,” and translates to “manifold,” which is fairly direct.

Charles Siegel is currently a postdoc at Kavli IPMU in Japan. He works on the geometry of the moduli space of curves.
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### 4 Responses to Japanese for mathematics: Manifold

1. img says:

I’d get James Heisig’s book on teaching yourself Kanji and a mathematical book/paper in Japanese that you intend to read. Katakana and Hiragana are a matter of pretty short, but consistent, work, so that’s the easier part of the story.
If you are learning to speak, then I have nothing useful to say as speaking Japanese has never been my goal.
Good luck.

2. Sam says:

Seconding the Heisig recommendation– especially for a mathematician. Heisig’s approach to kanji might remind you of linear algebra, the way he focuses on the constituent parts of kanji, building them up from simple to complex. (In mainstream Japanese education, both for JSL learners and for Japanese children too, the kanji are presented in an order based on their commonness, which often leads to the situation where kanji A is made up of kanji B+C+D, but A is taught years before B,C, or D. As an adult learner, presumably you want to learn all the kanji and quickly, so this order is nonsense).

It shouldn’t be too hard to pirate Heisig’s books if money is tight.

You should also look into using a spaced repetition system, such as Mnemosyne or Anki.

3. Thank you both for the recommendation of Heisig, I’ve already been looking into it, and am using a system like Anki as recommended by Sam.