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| author | jeanpouget-abadie <jean.pougetabadie@gmail.com> | 2015-05-18 19:27:59 +0200 |
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| committer | jeanpouget-abadie <jean.pougetabadie@gmail.com> | 2015-05-18 19:27:59 +0200 |
| commit | 99ce9bed50afa1b1f8b11e97d40f8642e6fed865 (patch) | |
| tree | 04ab8a03169f072ae20a708439cdc0bb4ccb19b9 /paper/sections/model.tex | |
| parent | 0ba2acb8819fb6ed4059f9115944035429d512a2 (diff) | |
| download | cascades-99ce9bed50afa1b1f8b11e97d40f8642e6fed865.tar.gz | |
fixed typos
Diffstat (limited to 'paper/sections/model.tex')
| -rw-r--r-- | paper/sections/model.tex | 15 |
1 files changed, 7 insertions, 8 deletions
diff --git a/paper/sections/model.tex b/paper/sections/model.tex index 26e1a8d..8d403e1 100644 --- a/paper/sections/model.tex +++ b/paper/sections/model.tex @@ -137,7 +137,7 @@ with inverse link function $f : z \mapsto 1 - e^{-z}$. Note that to write the Independent Cascade Model as a Generalized Linear Cascade Model, we had to introduce the change of variable $\Theta_{i,j} = \log(\frac{1}{1-p_{i,j}})$. The recovery results in Section~\ref{sec:results} -hold on the $\Theta_j$ parameters. Fortunately, the following lemma shows that +pertain to the $\Theta_j$ parameters. Fortunately, the following lemma shows that the recovery error on $\Theta_j$ is an upper bound on the error on the original $p_j$ parameters. @@ -178,7 +178,7 @@ independent cascade model with exponential transmission function (CICE) of~\cite{GomezRodriguez:2010, Abrahao:13, Daneshmand:2014}. Assume that the temporal resolution of the discretization is $\varepsilon$, \emph{i.e.} all nodes whose (continuous) infection time is within the interval $[k\varepsilon, - (k+1)\varepsilon)$ are considered infected at (discrete) time step $t$. Let + (k+1)\varepsilon)$ are considered infected at (discrete) time step $k$. Let $X^k$ be the indicator vector of the set of nodes `infected' before or during the $k^{th}$ time interval. Note that contrary to the discrete-time independent cascade model, $X^k_j = 1 \implies X^{k+1}_j = 1$, that is, @@ -292,13 +292,12 @@ measurements and not the number of cascades. \paragraph{Regularity assumptions} -We would like program~\eqref{eq:pre-mle} to be a convex program in order to +We would like program~\eqref{eq:pre-mle} to be convex in order to solve it efficiently. A sufficient condition is to -assume that $\mathcal{L}_i$ is a concave function. This will be the case if, -for example, $f$ and $(1-f)$ are both log-concave functions. Remember that -a twice-differentiable function $f$ is log-concave iff. $f''f \leq f'^2$. It is -easy to verify this property for $f$ and $(1-f)$ in the Independent Cascade -Model and Voter Model. +assume that $\mathcal{L}_i$ is a concave function, which is the case if $f$ and +$(1-f)$ are both log-concave functions. Remember that a twice-differentiable +function $f$ is log-concave iff. $f''f \leq f'^2$. It is easy to verify this +property for $f$ and $(1-f)$ in the Independent Cascade Model and Voter Model. Furthermore, the data-dependent bounds in Section~\ref{sec:main_theorem} will require the following regularity assumption on the inverse link function $f$: |
