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Negative Indices

  1. Jan 31, 2007 #1

    Apologies if this is in the wrong place but I've no idea what *it* does.....

    I should just mention that I'm currently doing my A-levels (16) and so my maths skills aren't that advanced....

    The problem:
    I've found a paper on the Kalman Filter on the internet (source: http://www.cs.unc.edu/~welch/media/pdf/kalman_intro.pdf)

    Now, I'm trying to get my head around it, but am struggling with what the "'super minus'" means at the bottom of page 2.

    I've asked all the teachers at school and none of them have any idea and keep telling me it's a typo and we've only dealt with indices that have a number in them.

    Could someone here please explain what it means?


  2. jcsd
  3. Jan 31, 2007 #2


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    Staff Emeritus
    Science Advisor

    Well, firstly, I don't know anything about the topic, but it is clearly not a typo! My take on it is that it just a notation: he is using the superscript - to distinguish the "a priori" measurements from the "a posteriori" measurements (with no superscript). In this sense the superscript - doesn't itself "mean" anything-- he could have used a ' or anything else to distinguish this, but just chose the -

    Hope that helps, but you may have to wait for someone who is familiar with the paper to confirm (or contradict) what I have just said!
  4. Feb 1, 2007 #3
    Thanks Cristo, that makes alot of sense.


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