# [Solved] Vector prime notation, what does it mean?

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I'm trying to implement this paper:

https://www.cs.ubc.ca/~van/papers/2013-TOG-MuscleBasedBipeds/2013-TOG-MuscleBasedBipeds.pdf

I'm having a hard time understanding Equation (17), specifically what rk' is and where it came from.

I know that rk is the moment arm (a vector), Pb is a position (vector), jk I think is the position of joint k, and Fb and Tare vectors calculated by equations (14) and (15). What is rk' though? I don't see any mention of it anywhere in the paper. Some google searches on vector prime notation lead me to believe that a vector with the prime symbol means the vector is tranposed. But I can see the transpose symbol already uses T, so is it really saying that vector rk is tranposed?

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apatriarca    2365
I haven't read the paper, but I think it is the derivative (with respect of time I guess).

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I haven't read the paper, but I think it is the derivative (with respect of time I guess).

I have successfully contacted the author. The ' was simply a harmless typo.