Kronecker product of identity and matrix product












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How is the following property true? Let $I$ be the identity matrix and $A$, $B$ be appropriately sized real matrices. Then
$$I otimes left(left( I otimes Aright) B right) = left( I otimes I otimes A right)left( I otimes Bright).$$
I think I'm missing something basic about the Kronecker product.










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    $begingroup$


    How is the following property true? Let $I$ be the identity matrix and $A$, $B$ be appropriately sized real matrices. Then
    $$I otimes left(left( I otimes Aright) B right) = left( I otimes I otimes A right)left( I otimes Bright).$$
    I think I'm missing something basic about the Kronecker product.










    share|cite|improve this question









    $endgroup$















      1












      1








      1





      $begingroup$


      How is the following property true? Let $I$ be the identity matrix and $A$, $B$ be appropriately sized real matrices. Then
      $$I otimes left(left( I otimes Aright) B right) = left( I otimes I otimes A right)left( I otimes Bright).$$
      I think I'm missing something basic about the Kronecker product.










      share|cite|improve this question









      $endgroup$




      How is the following property true? Let $I$ be the identity matrix and $A$, $B$ be appropriately sized real matrices. Then
      $$I otimes left(left( I otimes Aright) B right) = left( I otimes I otimes A right)left( I otimes Bright).$$
      I think I'm missing something basic about the Kronecker product.







      kronecker-product






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      asked Jan 28 at 8:24









      G. GareG. Gare

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          $begingroup$

          The kronecker product is associative, so
          $(Aotimes B)otimes C=Aotimes(Botimes C)$ and use that $(AB)otimes(CD)=(Aotimes C)(Botimes D)$. Now, you can just expand.






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          • $begingroup$
            Yes. I didn't think that $I = I^2$. Thanks!
            $endgroup$
            – G. Gare
            Jan 28 at 8:37











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          $begingroup$

          The kronecker product is associative, so
          $(Aotimes B)otimes C=Aotimes(Botimes C)$ and use that $(AB)otimes(CD)=(Aotimes C)(Botimes D)$. Now, you can just expand.






          share|cite|improve this answer









          $endgroup$













          • $begingroup$
            Yes. I didn't think that $I = I^2$. Thanks!
            $endgroup$
            – G. Gare
            Jan 28 at 8:37
















          1












          $begingroup$

          The kronecker product is associative, so
          $(Aotimes B)otimes C=Aotimes(Botimes C)$ and use that $(AB)otimes(CD)=(Aotimes C)(Botimes D)$. Now, you can just expand.






          share|cite|improve this answer









          $endgroup$













          • $begingroup$
            Yes. I didn't think that $I = I^2$. Thanks!
            $endgroup$
            – G. Gare
            Jan 28 at 8:37














          1












          1








          1





          $begingroup$

          The kronecker product is associative, so
          $(Aotimes B)otimes C=Aotimes(Botimes C)$ and use that $(AB)otimes(CD)=(Aotimes C)(Botimes D)$. Now, you can just expand.






          share|cite|improve this answer









          $endgroup$



          The kronecker product is associative, so
          $(Aotimes B)otimes C=Aotimes(Botimes C)$ and use that $(AB)otimes(CD)=(Aotimes C)(Botimes D)$. Now, you can just expand.







          share|cite|improve this answer












          share|cite|improve this answer



          share|cite|improve this answer










          answered Jan 28 at 8:28









          JamesJames

          965318




          965318












          • $begingroup$
            Yes. I didn't think that $I = I^2$. Thanks!
            $endgroup$
            – G. Gare
            Jan 28 at 8:37


















          • $begingroup$
            Yes. I didn't think that $I = I^2$. Thanks!
            $endgroup$
            – G. Gare
            Jan 28 at 8:37
















          $begingroup$
          Yes. I didn't think that $I = I^2$. Thanks!
          $endgroup$
          – G. Gare
          Jan 28 at 8:37




          $begingroup$
          Yes. I didn't think that $I = I^2$. Thanks!
          $endgroup$
          – G. Gare
          Jan 28 at 8:37


















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