Modifying Heat Kernel Equation for Graphs












2












$begingroup$


In spectral graph theory, I am aware that the following weight recurrence:



$$ w_t(v_i) = frac{1}{2}w_{t-1}(v_i)+sum_{v_j mid exists e_{ij} }frac{1}{2deg(v_i)} w_{t-1}(v_j) $$



Can be expressed in terms of eigen-vectors and eigenvalues of the Laplacian, $L=D-A$, nicely: $left( W_{ii} = frac{1}{2}, W_{ij} = frac{1}{deg(v_i)+deg(v_j)} right)$



$$ W^t u = sum_{k=1}^n lambda_i^t a_i v_i $$



For the following recursion formula, would this equation work?



$$ omega_t(v_i) = sum_{v_j mid exists e_{ij} }frac{omega_{t-1}(v_j)}{deg(v_i)} $$



$$ Omega^t u = sum_{k=1}^n (2lambda_i-1)^t a_i v_i $$



My logic is that "$2lambda_i$" will double the weight, and the "$-1$" will subtract off the weight that a vertex directs back onto itself. This is not for a class, my school does not offer spectral graph theory.










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$endgroup$












  • $begingroup$
    I got the first part from this video: “simons.berkeley.edu/events/openlectures2014-fall-4”
    $endgroup$
    – Zachary Hunter
    Jan 4 at 20:08










  • $begingroup$
    How does the heat kernel equation in the title come into play in the question?
    $endgroup$
    – mathreadler
    Jan 5 at 8:59






  • 1




    $begingroup$
    the first 5 minutes of the video I linked in the comments shows how this describes heat dispersion. if there's a more appropriate name, I'm all ears.
    $endgroup$
    – Zachary Hunter
    Jan 5 at 9:09










  • $begingroup$
    Ah ok, I did not see the link. Wow 79. That was like before C64 home computers. Must have been a big project making such computations back then.
    $endgroup$
    – mathreadler
    Jan 5 at 9:40










  • $begingroup$
    Heh, I was just waiting for him to go over to electrical flows, and he did.
    $endgroup$
    – mathreadler
    Jan 5 at 9:48
















2












$begingroup$


In spectral graph theory, I am aware that the following weight recurrence:



$$ w_t(v_i) = frac{1}{2}w_{t-1}(v_i)+sum_{v_j mid exists e_{ij} }frac{1}{2deg(v_i)} w_{t-1}(v_j) $$



Can be expressed in terms of eigen-vectors and eigenvalues of the Laplacian, $L=D-A$, nicely: $left( W_{ii} = frac{1}{2}, W_{ij} = frac{1}{deg(v_i)+deg(v_j)} right)$



$$ W^t u = sum_{k=1}^n lambda_i^t a_i v_i $$



For the following recursion formula, would this equation work?



$$ omega_t(v_i) = sum_{v_j mid exists e_{ij} }frac{omega_{t-1}(v_j)}{deg(v_i)} $$



$$ Omega^t u = sum_{k=1}^n (2lambda_i-1)^t a_i v_i $$



My logic is that "$2lambda_i$" will double the weight, and the "$-1$" will subtract off the weight that a vertex directs back onto itself. This is not for a class, my school does not offer spectral graph theory.










share|cite|improve this question











$endgroup$












  • $begingroup$
    I got the first part from this video: “simons.berkeley.edu/events/openlectures2014-fall-4”
    $endgroup$
    – Zachary Hunter
    Jan 4 at 20:08










  • $begingroup$
    How does the heat kernel equation in the title come into play in the question?
    $endgroup$
    – mathreadler
    Jan 5 at 8:59






  • 1




    $begingroup$
    the first 5 minutes of the video I linked in the comments shows how this describes heat dispersion. if there's a more appropriate name, I'm all ears.
    $endgroup$
    – Zachary Hunter
    Jan 5 at 9:09










  • $begingroup$
    Ah ok, I did not see the link. Wow 79. That was like before C64 home computers. Must have been a big project making such computations back then.
    $endgroup$
    – mathreadler
    Jan 5 at 9:40










  • $begingroup$
    Heh, I was just waiting for him to go over to electrical flows, and he did.
    $endgroup$
    – mathreadler
    Jan 5 at 9:48














2












2








2


1



$begingroup$


In spectral graph theory, I am aware that the following weight recurrence:



$$ w_t(v_i) = frac{1}{2}w_{t-1}(v_i)+sum_{v_j mid exists e_{ij} }frac{1}{2deg(v_i)} w_{t-1}(v_j) $$



Can be expressed in terms of eigen-vectors and eigenvalues of the Laplacian, $L=D-A$, nicely: $left( W_{ii} = frac{1}{2}, W_{ij} = frac{1}{deg(v_i)+deg(v_j)} right)$



$$ W^t u = sum_{k=1}^n lambda_i^t a_i v_i $$



For the following recursion formula, would this equation work?



$$ omega_t(v_i) = sum_{v_j mid exists e_{ij} }frac{omega_{t-1}(v_j)}{deg(v_i)} $$



$$ Omega^t u = sum_{k=1}^n (2lambda_i-1)^t a_i v_i $$



My logic is that "$2lambda_i$" will double the weight, and the "$-1$" will subtract off the weight that a vertex directs back onto itself. This is not for a class, my school does not offer spectral graph theory.










share|cite|improve this question











$endgroup$




In spectral graph theory, I am aware that the following weight recurrence:



$$ w_t(v_i) = frac{1}{2}w_{t-1}(v_i)+sum_{v_j mid exists e_{ij} }frac{1}{2deg(v_i)} w_{t-1}(v_j) $$



Can be expressed in terms of eigen-vectors and eigenvalues of the Laplacian, $L=D-A$, nicely: $left( W_{ii} = frac{1}{2}, W_{ij} = frac{1}{deg(v_i)+deg(v_j)} right)$



$$ W^t u = sum_{k=1}^n lambda_i^t a_i v_i $$



For the following recursion formula, would this equation work?



$$ omega_t(v_i) = sum_{v_j mid exists e_{ij} }frac{omega_{t-1}(v_j)}{deg(v_i)} $$



$$ Omega^t u = sum_{k=1}^n (2lambda_i-1)^t a_i v_i $$



My logic is that "$2lambda_i$" will double the weight, and the "$-1$" will subtract off the weight that a vertex directs back onto itself. This is not for a class, my school does not offer spectral graph theory.







spectral-graph-theory






share|cite|improve this question















share|cite|improve this question













share|cite|improve this question




share|cite|improve this question








edited Jan 9 at 9:31







Zachary Hunter

















asked Jan 4 at 5:13









Zachary HunterZachary Hunter

1,007313




1,007313












  • $begingroup$
    I got the first part from this video: “simons.berkeley.edu/events/openlectures2014-fall-4”
    $endgroup$
    – Zachary Hunter
    Jan 4 at 20:08










  • $begingroup$
    How does the heat kernel equation in the title come into play in the question?
    $endgroup$
    – mathreadler
    Jan 5 at 8:59






  • 1




    $begingroup$
    the first 5 minutes of the video I linked in the comments shows how this describes heat dispersion. if there's a more appropriate name, I'm all ears.
    $endgroup$
    – Zachary Hunter
    Jan 5 at 9:09










  • $begingroup$
    Ah ok, I did not see the link. Wow 79. That was like before C64 home computers. Must have been a big project making such computations back then.
    $endgroup$
    – mathreadler
    Jan 5 at 9:40










  • $begingroup$
    Heh, I was just waiting for him to go over to electrical flows, and he did.
    $endgroup$
    – mathreadler
    Jan 5 at 9:48


















  • $begingroup$
    I got the first part from this video: “simons.berkeley.edu/events/openlectures2014-fall-4”
    $endgroup$
    – Zachary Hunter
    Jan 4 at 20:08










  • $begingroup$
    How does the heat kernel equation in the title come into play in the question?
    $endgroup$
    – mathreadler
    Jan 5 at 8:59






  • 1




    $begingroup$
    the first 5 minutes of the video I linked in the comments shows how this describes heat dispersion. if there's a more appropriate name, I'm all ears.
    $endgroup$
    – Zachary Hunter
    Jan 5 at 9:09










  • $begingroup$
    Ah ok, I did not see the link. Wow 79. That was like before C64 home computers. Must have been a big project making such computations back then.
    $endgroup$
    – mathreadler
    Jan 5 at 9:40










  • $begingroup$
    Heh, I was just waiting for him to go over to electrical flows, and he did.
    $endgroup$
    – mathreadler
    Jan 5 at 9:48
















$begingroup$
I got the first part from this video: “simons.berkeley.edu/events/openlectures2014-fall-4”
$endgroup$
– Zachary Hunter
Jan 4 at 20:08




$begingroup$
I got the first part from this video: “simons.berkeley.edu/events/openlectures2014-fall-4”
$endgroup$
– Zachary Hunter
Jan 4 at 20:08












$begingroup$
How does the heat kernel equation in the title come into play in the question?
$endgroup$
– mathreadler
Jan 5 at 8:59




$begingroup$
How does the heat kernel equation in the title come into play in the question?
$endgroup$
– mathreadler
Jan 5 at 8:59




1




1




$begingroup$
the first 5 minutes of the video I linked in the comments shows how this describes heat dispersion. if there's a more appropriate name, I'm all ears.
$endgroup$
– Zachary Hunter
Jan 5 at 9:09




$begingroup$
the first 5 minutes of the video I linked in the comments shows how this describes heat dispersion. if there's a more appropriate name, I'm all ears.
$endgroup$
– Zachary Hunter
Jan 5 at 9:09












$begingroup$
Ah ok, I did not see the link. Wow 79. That was like before C64 home computers. Must have been a big project making such computations back then.
$endgroup$
– mathreadler
Jan 5 at 9:40




$begingroup$
Ah ok, I did not see the link. Wow 79. That was like before C64 home computers. Must have been a big project making such computations back then.
$endgroup$
– mathreadler
Jan 5 at 9:40












$begingroup$
Heh, I was just waiting for him to go over to electrical flows, and he did.
$endgroup$
– mathreadler
Jan 5 at 9:48




$begingroup$
Heh, I was just waiting for him to go over to electrical flows, and he did.
$endgroup$
– mathreadler
Jan 5 at 9:48










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