(Abstract Algebra 1) Units Modulo n

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  • Опубліковано 14 тра 2015
  • This video introduces the units modulo n and gives a sketch of a proof showing that they form a group under multiplication modulo n.

КОМЕНТАРІ • 50

  • @shirinisabekova5504
    @shirinisabekova5504 3 роки тому +12

    I have spent two days to find the right video to understand!!!! Thank you sooooooooooooo much! Keep posting such informative and comprehensive videos! You are a LEGEND!

  • @jyotishkosarkar249
    @jyotishkosarkar249 3 роки тому +2

    We are blessed that we have youtube as our one tutor❤️

  • @malarselvi5013
    @malarselvi5013 5 років тому +3

    i came with the doubt. clearly this video clears my doubt, thank you sir

  • @nyceric95
    @nyceric95 6 років тому +9

    everybody teaches math a different way and everyone learns math a different way. Anyone can learn math but everyone has a specific way in which they will fully understand the material as an overarching package. that completely depends on how and when different concepts are introduced during the course of the learning process. This might not work for everyone but it definitely introduces things in a way that is easy and simple to understand. sometime some people teaching a way where things are thrown in in an as-a-matter-of-fact way. I have tried learning through my professor and while i do understand some concepts i dont understand the material as an overarching package. An example is U(x). it was thrown in in my class and given a place in groups but i dint understand where it came from and what it meant for the bigger picture but the way you introduced it so organically was amazing almost like a brain ninja. i found myself seeing the justification of the introduction of this new concept into the world of groups and abstract algebra as a whole and by god it is beautiful to see. it brings me back to joy of learning calculus from different angle and understanding that they are not different forms of calc but the same picture seen through different lenses. if you ever find yourself having trouble with a math subject its not that its not for you its that you havent found someone who unravels it in a way where its a seamless path of understanding instead of facts and definitions thrown at you and expected for you to connect the dots. great series man!

    • @ngelemar
      @ngelemar 4 роки тому

      you just made me realize something that i will type the whole page, it's also about the understanding, this series also cleared everything to me too

  • @aneeshkhilnani2102
    @aneeshkhilnani2102 2 роки тому +1

    Thank you so much for your clarity, it is so helpful!

  • @user-ym7lw7vd1w
    @user-ym7lw7vd1w 3 місяці тому

    using a simple example of urs i was able to understand in 5 mins what i have been trying hard to study for a week thanks

  • @PunmasterSTP
    @PunmasterSTP 4 місяці тому

    Units modulo n? More like "Ultimately magnificent lecture; thanks again!" 👍

  • @user-ih4jf9xp9x
    @user-ih4jf9xp9x 4 роки тому +8

    How to show that there exists a* ∈ U(n) which was left out for us to do in 13:55
    (here I wrote a* instead of b as the element denoting the inverse of "a")
    We need to show: 1 ≤ a* < n and gcd(a*,n)=1
    First, show that 1 ≤ a* < n :
    (following from the video's proof about the existence of the integer b ∈ ℤ)
    Since a, n ∈ ℤ are given, by the Division Algorithm, there exist unique integers q and a* such that b=qn+a* with 1 ≤ a* < n.
    Here we can easily see that a* ≡ b (mod n)
    Second, show that gcd(a*,n)=1
    Suppose not. Let gcd(a*,n) = d > 1
    There exist integers m and f such that n=md and a*=fd.
    (following from the video's statement that n ❘ ab-1, ) since d ❘ n , we see that d ❘ ab-1 , so it should be the case that ab≡1(mod d).
    However, ab = a(qn+a*) = a(q(md)+fd) = (aqm+af)d ≡ 0 (mod n) CONTRADICTION

  • @wdlang06
    @wdlang06 6 років тому +1

    so clear! Thanks a lot!

  • @UrinatingTheCrowd
    @UrinatingTheCrowd 6 років тому

    clear and to the point.. very nice

  • @Rahul-pq7we
    @Rahul-pq7we 2 роки тому

    Thank you sir , it is easy to understandable ✨✨

  • @jaiprakash890
    @jaiprakash890 5 років тому

    videos are awesome bro😃

  • @Parameswar_Ghosal
    @Parameswar_Ghosal 5 років тому

    you are such a brilliant........

  • @rnma14
    @rnma14 7 років тому +1

    You are brilliant :) !!

  • @areebayasmeen6435
    @areebayasmeen6435 4 роки тому

    Does this theorem only for multiplication? Not for addition?

  • @giorgosconstantinou7285
    @giorgosconstantinou7285 2 роки тому

    LOVE YOU BROOOOO

  • @benderbendingrofriguez3300
    @benderbendingrofriguez3300 4 роки тому +1

    This was a very helpful video, thank you very much you did help a lot. If you ever need help, let me know. I give some good hand job.

  • @princesszoni1575
    @princesszoni1575 5 років тому +1

    ####Excellent superb sir.
    Will u pls tell me a Normal group defination in one meaningful line?

    • @marvinescobar4821
      @marvinescobar4821 5 років тому

      A group is a set of objects under a single operation that satisfies the axioms of closure, associativity, identities, and inverses.

  • @elsiex1662
    @elsiex1662 3 роки тому

    Thank you so much Sir!!!!

  • @peterp2067
    @peterp2067 2 роки тому

    very good,,very understandable

  • @zeenatreddy7692
    @zeenatreddy7692 2 роки тому

    five bloody stars! I finally understand!!!!

  • @Harnaam
    @Harnaam 6 років тому

    Thank you sir

  • @malarselvi5013
    @malarselvi5013 5 років тому

    what are the subgroups of multiplication modulo 11?

    • @TheOiseau
      @TheOiseau 2 роки тому

      The trivial group and Z11 itself. There are no others since 11 is prime.

  • @dee8163
    @dee8163 4 роки тому

    How do we know b belongs to U?

  • @yourbroo3430
    @yourbroo3430 Рік тому

    thank you very much sir :)

  • @jadda78
    @jadda78 3 роки тому

    Thanks 👍

  • @02shahana
    @02shahana 8 років тому

    2 is prime number so hw can we generlise tht prime numbers can included in this group

    • @nyceric95
      @nyceric95 6 років тому

      but 2 and 8 are not relatively prime

  • @bimalsirg
    @bimalsirg 6 років тому

    Sir, please solve this in video.find the order of each element in the group z5 - {[O]}, . 5

  • @SADDAMHUSSAIN-mw3cv
    @SADDAMHUSSAIN-mw3cv Рік тому

    Thank you sir...

  • @mobilevideography.3896
    @mobilevideography.3896 6 років тому

    Im not clear how to find inverse of 1357..?

    • @joseandrew5194
      @joseandrew5194 6 років тому +1

      look at what multiplies those numbers and gives you back the identity, in this case 1. So 3 * 3 = 9, 9 mod 8 = 1. Therefore the inverse of 3 is 3

  • @analiewagasahit6012
    @analiewagasahit6012 2 роки тому

    Anyone can help me, to find what are the binary properties in the set. 🥺🥺🥺 I'm confused where to find it. Thank you so much.
    Eventually, I'm answering mod 7

    • @mathematicia
      @mathematicia 2 роки тому

      Binary properties. ..
      Is it union intersection , subtraction ?

  • @ToanPham-wr7xe
    @ToanPham-wr7xe 5 місяців тому

    😮

  • @priyavats1847
    @priyavats1847 11 місяців тому

    Is it applicable only for multiplication??

    • @priyavats1847
      @priyavats1847 11 місяців тому

      U(8) concept

    • @cjjk9142
      @cjjk9142 8 місяців тому

      You can do it for addition but there’s a slightly different approach

  • @harshchaudhary6984
    @harshchaudhary6984 5 років тому

    But you haven't proved that gcd(b,n)=1 while finding inverse

    • @AnkitKumar-js9rx
      @AnkitKumar-js9rx 4 роки тому

      He left that part to us

    • @yashuppot3214
      @yashuppot3214 4 роки тому

      Units mod n has already excluded any b that does not satisfy this

  • @jaggichinnu8286
    @jaggichinnu8286 3 роки тому

    Tq sir it so help ful to understand multiplicative madulo

  • @deepaksaxena941
    @deepaksaxena941 6 років тому

    Sir ji hidi se bataiye

  • @nacht3894
    @nacht3894 Рік тому

    Thank you sir