Decomposition of a block matrix related to graph Laplacians












0














I'm working on graph networks in a communications problem and I have trouble understanding how to work with this $3 times 3$ block matrix related to graph Laplacians:



D =
begin{bmatrix}
rho D_0 L_{+} & -D_0 & D_0 \
rho^{2}L_-D_0L_+ & textbf{I}-rho L_-D_0 & rho L_-D_0 \
textbf{0} & textbf{0} & textbf{I}
end{bmatrix}



where, begin{equation*}
D_0 = (textbf{I} + 2rho W)^{-1}
end{equation*}



$L_{+}$ and $L_{-}$ are the unsigned and signed Laplacian matrices of the underlying graph and $W$ is the diagonal matrix with diagonal entry $(i,i)$ having the number of neighbours of node $i$. These matrices are also $positive thinspace semidefinite$.



$rho$ is just a constant.



The graphs are also $balanced thinspace digraphs$, in the sense that if two nodes are connected, there are two edges between them; one from each node to the other.



All matrices embedded in the block matrix are $n times n$ matrices.



What I aim to do are to understand the $spectral$ properties of $D^k$ through some decomposition theorems (This is what I think will help me the most and I would like some references regarding this). I have read about $Schur thinspace decomposition$ but I could find literature only on $2 times 2$ block matrices. More specifically, I would like to understand what happens to $D^{infty}$(i.e its spectral properties).










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    0














    I'm working on graph networks in a communications problem and I have trouble understanding how to work with this $3 times 3$ block matrix related to graph Laplacians:



    D =
    begin{bmatrix}
    rho D_0 L_{+} & -D_0 & D_0 \
    rho^{2}L_-D_0L_+ & textbf{I}-rho L_-D_0 & rho L_-D_0 \
    textbf{0} & textbf{0} & textbf{I}
    end{bmatrix}



    where, begin{equation*}
    D_0 = (textbf{I} + 2rho W)^{-1}
    end{equation*}



    $L_{+}$ and $L_{-}$ are the unsigned and signed Laplacian matrices of the underlying graph and $W$ is the diagonal matrix with diagonal entry $(i,i)$ having the number of neighbours of node $i$. These matrices are also $positive thinspace semidefinite$.



    $rho$ is just a constant.



    The graphs are also $balanced thinspace digraphs$, in the sense that if two nodes are connected, there are two edges between them; one from each node to the other.



    All matrices embedded in the block matrix are $n times n$ matrices.



    What I aim to do are to understand the $spectral$ properties of $D^k$ through some decomposition theorems (This is what I think will help me the most and I would like some references regarding this). I have read about $Schur thinspace decomposition$ but I could find literature only on $2 times 2$ block matrices. More specifically, I would like to understand what happens to $D^{infty}$(i.e its spectral properties).










    share|cite|improve this question

























      0












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      0







      I'm working on graph networks in a communications problem and I have trouble understanding how to work with this $3 times 3$ block matrix related to graph Laplacians:



      D =
      begin{bmatrix}
      rho D_0 L_{+} & -D_0 & D_0 \
      rho^{2}L_-D_0L_+ & textbf{I}-rho L_-D_0 & rho L_-D_0 \
      textbf{0} & textbf{0} & textbf{I}
      end{bmatrix}



      where, begin{equation*}
      D_0 = (textbf{I} + 2rho W)^{-1}
      end{equation*}



      $L_{+}$ and $L_{-}$ are the unsigned and signed Laplacian matrices of the underlying graph and $W$ is the diagonal matrix with diagonal entry $(i,i)$ having the number of neighbours of node $i$. These matrices are also $positive thinspace semidefinite$.



      $rho$ is just a constant.



      The graphs are also $balanced thinspace digraphs$, in the sense that if two nodes are connected, there are two edges between them; one from each node to the other.



      All matrices embedded in the block matrix are $n times n$ matrices.



      What I aim to do are to understand the $spectral$ properties of $D^k$ through some decomposition theorems (This is what I think will help me the most and I would like some references regarding this). I have read about $Schur thinspace decomposition$ but I could find literature only on $2 times 2$ block matrices. More specifically, I would like to understand what happens to $D^{infty}$(i.e its spectral properties).










      share|cite|improve this question













      I'm working on graph networks in a communications problem and I have trouble understanding how to work with this $3 times 3$ block matrix related to graph Laplacians:



      D =
      begin{bmatrix}
      rho D_0 L_{+} & -D_0 & D_0 \
      rho^{2}L_-D_0L_+ & textbf{I}-rho L_-D_0 & rho L_-D_0 \
      textbf{0} & textbf{0} & textbf{I}
      end{bmatrix}



      where, begin{equation*}
      D_0 = (textbf{I} + 2rho W)^{-1}
      end{equation*}



      $L_{+}$ and $L_{-}$ are the unsigned and signed Laplacian matrices of the underlying graph and $W$ is the diagonal matrix with diagonal entry $(i,i)$ having the number of neighbours of node $i$. These matrices are also $positive thinspace semidefinite$.



      $rho$ is just a constant.



      The graphs are also $balanced thinspace digraphs$, in the sense that if two nodes are connected, there are two edges between them; one from each node to the other.



      All matrices embedded in the block matrix are $n times n$ matrices.



      What I aim to do are to understand the $spectral$ properties of $D^k$ through some decomposition theorems (This is what I think will help me the most and I would like some references regarding this). I have read about $Schur thinspace decomposition$ but I could find literature only on $2 times 2$ block matrices. More specifically, I would like to understand what happens to $D^{infty}$(i.e its spectral properties).







      matrix-decomposition algebraic-graph-theory spectral-graph-theory






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      asked Dec 1 at 4:11









      Nandan Sriranga

      11




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