some svm typos corrected
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@@ -342,7 +342,7 @@ possible margin $M$. Before we proceed, we need to remind ourselves
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about Lagrangian multipliers.
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!split
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===== A quick reminder on Lagrangian multipliers =====
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===== A quick Reminder on Lagrangian Multipliers =====
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Consider a function of three independent variables $f(x,y,z)$ . For the function $f$ to be an
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extreme we have
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@@ -394,7 +394,7 @@ variables.
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Then $dz$ is no longer arbitrary.
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!split
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===== Adding the muliplier =====
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===== Adding the Multiplier =====
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However, we can add to
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!bt
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@@ -441,7 +441,7 @@ If we have a set of constraints $\phi_k$ we have the equations
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!et
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!split
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===== Setting up the problem =====
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===== Setting up the Problem =====
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In order to solve the above problem, we define the following Lagrangian function to be minimized
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!bt
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\[
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@@ -634,11 +634,11 @@ y_i(\bm{w}^T\bm{x}_i+b) -(1-\xi_) \geq 0 \hspace{0.1cm}\forall i.
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!split
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===== Kernels and non-linearity =====
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The cases we have studied till were all characterized by two classes
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The cases we have studied till now, were all characterized by two classes
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with a close to linear separability. The classifiers we have described
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so far find linear boundaries in our input feature space. It is
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possible to make our procedure more flexible by exploring the feature
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space using other basis expansions such higher-order polynomials,
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space using other basis expansions such as higher-order polynomials,
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wavelets, splines etc.
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If our feature space is not easy to separate, as shown in the figure
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@@ -724,7 +724,7 @@ y_i(\bm{w}^T\bm{z}_i+b)= 1 \hspace{0.1cm}\forall i,
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\]
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!et
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from which we also find $b$.
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To compute $\bm{z}_i^T\bm{z}_j$ we define the kerne $K(\bm{x}_i,\bm{x}_j)$ as
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To compute $\bm{z}_i^T\bm{z}_j$ we define the kernel $K(\bm{x}_i,\bm{x}_j)$ as
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!bt
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\[
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K(\bm{x}_i,\bm{x}_j)=\bm{z}_i^T\bm{z}_j= \phi(\bm{x}_i)^T\phi(\bm{x}_j).
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@@ -746,7 +746,7 @@ the dot product $(\bm{x}_i^T\bm{x}_j)^2$.
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This leads to the so-called
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kernel trick and the result leads to the same as if we went through
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the trouble of performing the transformation
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$(\phi(\bm{x}_i)^T\phi(\bm{x}_j)$ during the SVM calculations.
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$\phi(\bm{x}_i)^T\phi(\bm{x}_j)$ during the SVM calculations.
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!split
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