# Tagged Questions

58 views

### Linear Programming? [on hold]

An agriculture company has 80 tons of fertilizer Alpha and 120 tons of fertilizer Bravo. The company mixes these fertilizer into two products. Product Super requires 2 parts of fertilizer A and 1 part ...
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### linear inequalities using LP solutions not from simplex

I am trying to solve a set of inequalities using linear programming (LP) with objective function set as a constant. Usually this set of inequalities would have many solutions all of them in the ...
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### Feasability of infinite number of linear inequalities

Consider a continuous function $f:A\to\mathbb{R}^N$ for a closed interval $A\subset \mathbb{R}$. Are there suffieint or necessary conditions for the existence of a solution $w\in\mathbb{R}^N$ such ...
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### Prove solution does not exist for inequalities system

I have an inequalities sytem like the following: Example > x+y+z <= A > x+y <= B > x+z > C > y+z > D > x >= E Let A,B,C,D,E be any ...
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### Linear Inequalities - Allocation Problem

The problem at hand can be summarized as follows: we have to allocate a ressource to $n$ production units. The allocation to production unit $i$ is $x_i$. Each of the production unit will produce at ...
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### Given a set of inequalities, use what algorithm to minimize one variable?

I have the following set of inequalities: $$C_1 \le y-T_1x_1 \lt C_1+D_1$$ $$C_2 \le y-T_2x_2 \lt C_2+D_2$$ $$C_3 \le y-T_3x_3 \lt C_3+D_3$$ where $x_1, x_2, x_3$ and $y$ are non-negative integer ...
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### Modeling 4 people going to same place over 3 different places for at least 5 days

I'm trying to model a linear programming task with the condition 4 people going to the same place among 3 different places for at least 5 days. I have the variables for the time spend each person in ...
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### Simplex on Linear Program with equations

My linear program instead of inequations also contains one equation. I do not understand how to handle this in every tutorial I searched the procedure is to add slack variables to convert the ...
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### Compute the point of contraction of a bounded region in $\mathbb{R}^n$

Say we have a list of linear inequalities that define a bounded region in $\mathbb{R}^n$. These inequalities are: $a_1 \cdot x \ge c_1, \dots, a_k \cdot x \ge c_k$. Assume general position (i.e. it ...
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### Checking the existence of a solution for a set of linear equality and ineaulity equations

I would like to know if there is a method to check the existence of the solution for a given set of linear equations composed with both equalities and inequalities? I'm not interested in the solution, ...
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### Solving an overdetermined system of inequalities using null-space arguments

The solutions to a linear system of equations: $$A\cdot x = b$$ (where $x$ is a $(n\times 1)$ column vector, $b$ is a $(m\times 1)$ column vector and $A$ is $(m\times n)$ matrix) can all be ...
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### linear equations with inequality constraints

The problem is, given a set of linear equations $Ax=b$ such that the system is under-determined, and a set of linear inequalities $Cx\geq 0$, find a solution for the system. Does anyone know a general ...
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### Dimension of solution space for system of linear inequalities

Let's say I have a system of inequalities: $Ax \leq g$ for some $A \in \mathbb{R}^{4\times4}$, $x \in \mathbb{R}^4$, $g \in \mathbb{R}^4$, and $A$ is full rank. Here, the $\leq$ denotes element-wise ...
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### Farkas Lemma proof

I am trying to prove the Farkas Lemma using the Fourier-Motzkin elimination algorithm. From Wikipedia: Let A be an $m \times n$ matrix and $b$ an $m$-dimensional vector. Then, exactly one of the ...
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### Minimal set of inequalities

I have a set of $m$ linear inequalities in $R^n$, of the form $$A x \leq b$$ These are automatically generated from the specification of my problem. Many of them could be removed because they are ...
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### Convex hull of sets defined by (in)equalities

If you define the convex hull of a set $X$ as the set of all convex combinations of elements of $X$, it becomes difficult to decide if a given element $w$ belongs or not to $conv(X)$ (You have to ...
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### Does the triangle inequality suffice to prove all minimum results on sums of absolute values of affine functions?

The title says it all ... more formally : let $n \geq 1$, and let $a_1, a_2 , \ldots ,a_n$ be positive numbers, let $b_1, b_2 , \ldots ,b_n$ be real numbers. Consider for $x\in {\mathbb R}$,  ...
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### How to calculate volume given by inequalities?

I need to find the volume of the 3d space that is given by the following conditions: \begin{array}{c} 0 < x_1 < 1\\ 0 < x_2 < 1\\ 0 < x_3 < 1\\ x_1 + x_2 + x_3 < a. ...
I have $a^\intercal M b > 0$, where $\forall a_i > 0$, $\forall b_j > 0$, and M is known. I'd like to find a tight linear constraint on $b$ which is independent of $a$ (other than the ...