diff --git a/Latex/ilp.tex b/Latex/ilp.tex new file mode 100644 index 0000000000000000000000000000000000000000..cf5be8240969d3e4f89b88c3bda2d1a3c8377352 --- /dev/null +++ b/Latex/ilp.tex @@ -0,0 +1,21 @@ +\section{Linear Programming} \raggedbottom +Linear programming is a technique to minimize linear functions. +A linear programm (LP) consists of a objective function, which is minimized with respect to a set of linear inequalities. \\ +\\ +Linear programms can be expressed as +\[min\{c^Tx : Ax \geq b, x \geq 0\}\] +$b \in \mathbb{R}^n$ and $c \in \mathbb{R}^n$ are constant vectors. $Ax \leq b$ denotes the inequalities which have to be respected. $A \in \mathbb{R}^{m \times n}$ is a matrix containing the coefficients of the $m$ inequalities. $c^Tx \in R$ is the objective function which is minimized. +$x \in \mathbb{R}$ is a vector describing possible solutions. If $x \in \mathbb{R}$ obeys all inequalities it is called a feasible solution. A solution $x^*$ is optimal if respects all inequalities and is minimal. +\\ +\\ +Integer linear programms (ILPs) are linear programms with the additional restriction that all variables have to be integers: $x \in \mathbb{Z}$. +The decision variant of an ILP is NP-complete. +\\ +In this thesis we use a more readable notation which does not completely sticks to this definition. We write down the inequalities in a sum notation. (Maybe an example?) But it is possible to transform them into the matrix notation. +\\ +\\ +Decision problems can be modelles with ILPs. Every variable $x_i \in \{0,1\}$ denotes a possible decision. In our case we assign a decision variable for each vertex to decide if it is included in a dominating set or not. + + +\pagebreak +