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Contents
Computer assistance for ``discovering'' formulas in system engineering and operator theory
J. William Helton
- Mark Stankus
Contents
Strategies and Applications
Introduction
Background on polynomial equations and Ideals
A few polynomial equations
Solutions of Polynomial Equations And Ideals
A highly idealized picture
Basic ``idealized'' operations
Idealized strategies
New derivations of classical theorems: idealized picture
A practical picture
NCProcess commands
New derivations of classical theorems: practical picture
Algorithms and their properties
Obtaining smaller Bases; shrinking
Noncommutative elimination theory
A practical notation
Computational concerns
Acknowledgements
Prestrategy
Elimination
NCProcess
The input and output of NCProcess
A simple example of NCProcess1
Categories
Comparison of NCProcess and Categorize
Prestrategy
When to stop; the end game
Example: The Bart-Gohberg-Kaashoek-Van Dooren Theorem
Background
The problem
Solution via a prestrategy
The end game
Concluding Remarks
Examples: Matrix Completion Problems
The partially prescribed inverse problem
Unitary case of Parrot's Lemma
Strategies and motivated unknowns
Strategy
Computing decompositions
NCCollectOnVariables
Introducing a new motivated unknown
Example: Solving the
Control Problem
Problem statement
Solving (
HGRAIL
) using NCProcess
Step 1 : Process and Collect
Step 2: The user attacks
Step 3
Step 4
End game
Monomial orders
Summary
Appendix to Part I: More details on NCCollectOnVariables
Collecting against a set of expressions
NCCollectOnVariables
Theory and more details
Background on Ideals and Gröbner Bases
The Reduction Process
The Basis Algorithm
A Gröbner Basis Theorem on Elimination Ideals
Finding a small generating set for an ideal
The need to consider small generating sets
Preview of operations
The SmallBasis Operation
Approximation of the SmallBasis operation
The ShrinkBasis Operation
Gröbner Graph: Background for the RemoveRedundant Operation
Gröbner Basis Background
The graph
Definition of a Gröbner Graph
The RemoveRedundant operation
Respect for categories
Idealized shrinking by category
Practical shrinking by category
Remove Redundant Protected
Speeding up runs
DegreeCap and DegreeSumCap
Monomial Orders vs. Run time
Details of NCProcess
NCProcess1 command
NCProcess2 command
Adjoints
Example of discovering
Formal descriptions of pure lex and multigraded lex
An ordering on
Formal description of pure lex
Formal description of multigraded lex
Engineering motivation for the
Control Problem (not for publication)
System definitions
Energy balance equations
About this document ...
Helton
Wed Jul 3 10:27:42 PDT 1996