Simplified: Girsanov Theorem for Brownian Motion (Change of Probability Measure)

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  • Опубликовано: 31 окт 2020
  • Explains the Girsanov’s Theorem for Brownian Motion using simple visuals. Starts with explaining the probability space of brownian motion paths, and once the probability measure is introduced, then shows how the change of probability measure looks like visually. The video ends with outlining the relationship between conditional expectation under the two measures.

Комментарии • 47

  • @aidenshen8343
    @aidenshen8343 2 года назад +8

    The professor recommends the video to us! Thanks!

    • @quantpie
      @quantpie  2 года назад +1

      it is very kind of them! You're welcome!

  • @abigail-sothoth362
    @abigail-sothoth362 3 года назад +11

    The best video I have found on Girsanov Theorem. Thank you so much!

    • @quantpie
      @quantpie  3 года назад +1

      You're very welcome! thank you!

  • @thiminhthinguyen6414
    @thiminhthinguyen6414 Год назад +1

    Your visualization is truly amazing. I have had a hard time constructing the probability measure of Brownian motion in my head and thanks to your explanation, it is clear to me now.

  • @AlexRodriguez-bt5jb
    @AlexRodriguez-bt5jb 3 года назад +7

    So grateful for you and this channel. Thank you so much for your work

    • @quantpie
      @quantpie  3 года назад

      You’ re welcome! Thank you!

  • @bramgriffioen5436
    @bramgriffioen5436 9 месяцев назад

    Thank you so much!! Really resourceful explanation, to get some insights into this abstract formula !

  • @StratosFair
    @StratosFair Год назад

    Wonderful explanation of Girsanov's theorem

  • @uminhtetoo
    @uminhtetoo 10 месяцев назад

    Thank you so much for sharing, Sir.

  • @hbbexxter4666
    @hbbexxter4666 3 года назад +2

    Fantastic. Absolutely fantastic! You bring stochastic calculus to life and make it finally understandable for mortal people as well.

    • @quantpie
      @quantpie  3 года назад

      Many thanks for the kind words!!

  • @mariuslotz8896
    @mariuslotz8896 3 года назад

    Thanks, easy to understand

  • @adokoka
    @adokoka 2 года назад +2

    Clean explanation!

    • @quantpie
      @quantpie  2 года назад

      Glad it was helpful! many thanks!

  • @sheldonjallen
    @sheldonjallen 3 года назад +2

    That was awesome! Thank you for that patient, cogent explanation!

  • @jxliu6375
    @jxliu6375 3 года назад +1

    Love the video! Thanks!

    • @quantpie
      @quantpie  3 года назад

      Glad you enjoyed it! You're welcome!

  • @milinds4161
    @milinds4161 3 года назад +1

    The very best intuitive explanation on the net. Thanks so much!

  • @qiguosun129
    @qiguosun129 5 месяцев назад

    Great ! thanks!

  • @War4Skills
    @War4Skills 3 месяца назад

    Hi, thank you for the great video, it truly made me understand the concept of changing probability measures way easier. I never knew it was actually that straightforward! Is it possible to share your slides? I would like to take notes on them if you don't mind :)

  • @devyash313
    @devyash313 3 года назад +1

    Very intuitive explanation. Thank you!

    • @quantpie
      @quantpie  3 года назад

      Glad it was helpful!

  • @user-wc7em8kf9d
    @user-wc7em8kf9d 3 года назад +1

    Amazing explanation! Thank you so much for this.

    • @quantpie
      @quantpie  3 года назад

      thanks! You're very welcome!

  • @vitalimueller6209
    @vitalimueller6209 3 года назад +3

    You have great content, well done

    • @quantpie
      @quantpie  3 года назад

      Thank you so much 👍

  • @williamqiu1917
    @williamqiu1917 Год назад

    You mentioned in the video that we don't need to worry about the sigma algebra too much. But the problem always hugged me a little, can't the sigma algebra be too small for something we are describing or is there a theorem stating for any problem we can find a suitable sigma algebra.

  • @curisity
    @curisity 3 года назад +1

    Amazing explanation !

  • @yanisbarillon3597
    @yanisbarillon3597 Год назад

    At 18:46 you made a mistake on the sign of the term in t in the radon nikodyn dQ/dP density but really thank you good explanation

  • @yanisbarillon3597
    @yanisbarillon3597 Год назад

    First, thanks for your video it's quite clear to relate with practical and visual example. But around 7 min you said that the proba that the brownian pass through the 3 gates is the product because of independance but there is only independance of Wt2-Wt1 with Wt1 not of Wt2 with Wt1 isn't it ? (So my question is : Is there an error or am I missing something)

    • @peterpaton7817
      @peterpaton7817 11 месяцев назад

      The independence between the brownian increments (the change in the process between these times)

  • @abhinavsaxena2388
    @abhinavsaxena2388 2 года назад +1

    I am new to computational finance. With so many videos, suggest should be the first 5 topics to view ?

    • @quantpie
      @quantpie  2 года назад

      thanks! Just replied to your other comment, apologies for the slow response!

  • @ajith009100
    @ajith009100 3 года назад +3

    Hi, great content ! I lost a bit at 17:34, how did you get at the dQ/dP = exp(-2.5W -0.5*2.5*t^2) ?

    • @Beacher1085
      @Beacher1085 3 года назад +4

      Check at 18:40, bottom right-hand side. You know μ from previous step.
      (He's applying Nadon-Rikodym derivative. en.m.wikipedia.org/wiki/Girsanov_theorem)

    • @quantpie
      @quantpie  3 года назад +1

      thanks!

  • @ROni_ROmio
    @ROni_ROmio 3 года назад +2

    Thanks bro, could you do video about le new FMM Foward Market Model and explain the changes VS LMM please,..? Many Thanks

    • @quantpie
      @quantpie  3 года назад +1

      thanks! it is on the to do list!

    • @fabioniski3316
      @fabioniski3316 3 года назад +1

      Yes a video on the FMM from the quantpie would be a huge hit.

  • @NA-rq5dw
    @NA-rq5dw 3 года назад +1

    Should it not be -2.5dt?

    • @quantpie
      @quantpie  3 года назад

      Whereabout please? dW has drift zero under P, drift of -2.5 under Q. The tilde version has drift zero under Q, so under Q you will to add 2.5 to dW to get the tilde version. Does that answer your question?

    • @danielmcdouall4056
      @danielmcdouall4056 3 года назад

      @@quantpie I think they mean the dt coefficient for the dWt tilde. The gradient is downward sloping so should the vale not be negative?

    • @danielmcdouall4056
      @danielmcdouall4056 3 года назад

      value*