Questions tagged [terminology]

For questions about the definition or meaning of terms used within Operations Research. Do not use this tag for questions about notation.

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5
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1answer
60 views

Combined arc capacity constraints in network flows

Consider the network flow polyhedron for a directed graph $G = (N, A)$. Along with the standard flow-balance and single-arc capacity constraints, we are faced with additional constraints which enforce ...
4
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1answer
51 views

What is the name of the graph where any edge is part of a cycle?

I wonder if there is a special category for this kind of graphs, I am thinking of a bidirectional graph but it would also be interesting in the cases when it is undirected. I am thinking of something ...
5
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1answer
46 views

Terminology for continuous planning, real-time planning, non-disruptive replanning, overconstrained planning, backup planning etc

In the past 14 years, when dealing with enterprise planning challenges, I've encountered multiple challenges of "repeated planning" and "planning agility" in general. At some point,...
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0answers
68 views

Analysis model vs. executable implementation of model?

In my post-graduate research and subsequent career in operational analysis, the difference between following seems to have become clearer with the years: (1) a model of a problem or operations in the ...
6
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2answers
156 views

What is the definition for an integer-friendly constraint?

I have seen some papers claiming that their proposed model is integer-friendly. I would like to get more information about what type of constraints we can call integer-friendly. Probably, it can be ...
4
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1answer
113 views

What is the meaning of monotone hazard rate (MHR) distribution?

It might be somewhat irrelevant to this forum but I think that many people here are familiar with this concept. I have seen that many papers assume that customers' valuation ($F$) is a monotone hazard ...
12
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2answers
297 views

Dual bounds of integer programming problems

I often read in papers when branch-and-X algorithms are used to solve mixed integer programming problems, that the lower bound (in the minimization case) obtained from solving a linear programming ...
8
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3answers
154 views

Difference between “Optimization” and “Constrained Optimization”?

(Another OR noob question) As I'm trying to learn about OR and Optimization methods for work, I'm having a hard time understanding the difference between "Optimization" and "Constrained Optimization"...
10
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2answers
368 views

Geometric programming: Why are the constraints defined to be less than/equal to 1?

In a simple convex optimisation problem, the standard form is given by \begin{align}\min_{\bf x}&\qquad f({\bf x})\\\text{s.t.}&\qquad g_i({\bf x})\le 0,\quad i=1,\cdots,m\\&\qquad h_j({\...
14
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2answers
1k views

Polyhedra, Polyhedron, Polytopes and Polygon

About Polyhedra, Polyhedron, Polytopes and Polygon, what do they mean in the context of linear programming and what is the difference between them?
22
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4answers
2k views

What is a solution?

Consider a standard optimization problem: Minimize an objective function with respect to constraints. My question is: What does the term "solution of the optimization problem" mean? At first I ...
27
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5answers
2k views

Optimization terminology: “Exact” v. “Approximate”

In optimization literature, I frequently see solution methods termed "exact" or "approximate". (I use the term "method" here because I suspect exactness, or its lack, is a function of both algorithm ...
34
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1answer
896 views

What are common and not so common abbreviations in Operations Research?

Many abbreviations are used in Operations Research. For example, we have abbreviations for problem classes (LP, MIP), solution methods (IPM), and specific problems (TSP, VRP). Which abbreviations are ...
13
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1answer
674 views

What is quadratization?

In the context of discrete optimization, what exactly does it mean to "quadratize" a function? The term seems to be used mainly by operations researchers, in my experience.
12
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0answers
106 views

Has the expressibility of 'non-integrality testing' as extension to MILP been studied before?

It turns out that extending MILP with any of the constraints $y=\lfloor x\rfloor$, $y=\lceil x\rceil$, $0 < x$, or $x\notin \mathbb{Z}$ is 'equally hard'. (see my answer here, and below) ...