The document discusses several topics in proof complexity and matrix algebra that can be expressed in Quantified Permutation Frege (QPK). It summarizes Mulmuley's algorithm for computing matrix rank in NC2 and shows how the Steinitz Exchange Lemma can be used to prove properties like the existence of matrix powers and the Cayley-Hamilton theorem in the theory of Quantified Propositional Logic with Arithmetic (QLA). Specifically, it shows that QLA can prove Cayley-Hamilton using Steinitz Exchange Lemma and the principle of Strong Linear Independence.
How to find a cheap surrogate to approximate Bayesian Update Formula and to a...Alexander Litvinenko
We suggest the new vision for classical Bayesian Update formula. We expand all ingredients in Polynomial Chaos Expansion and write out a new formula for Bayesian* update of PCE coefficients. This formula is derived from Minimum Mean Square Estimation. One starts with prior PCE, take measurements into account, and obtain posterior PCE coefficients, without any MCMC sampling.
Non-sampling functional approximation of linear and non-linear Bayesian UpdateAlexander Litvinenko
We offer a non-sampling functional approximation of non-linear surrogate to classical Bayesian Update formula. We start with prior Polynomial Chaos Expansion (PCE), express log-likelihood in a PCE basis and obtain a new posterior PCE.
Main IDEA is to update not probability density, but basis coefficients.
How to find a cheap surrogate to approximate Bayesian Update Formula and to a...Alexander Litvinenko
We suggest the new vision for classical Bayesian Update formula. We expand all ingredients in Polynomial Chaos Expansion and write out a new formula for Bayesian* update of PCE coefficients. This formula is derived from Minimum Mean Square Estimation. One starts with prior PCE, take measurements into account, and obtain posterior PCE coefficients, without any MCMC sampling.
Non-sampling functional approximation of linear and non-linear Bayesian UpdateAlexander Litvinenko
We offer a non-sampling functional approximation of non-linear surrogate to classical Bayesian Update formula. We start with prior Polynomial Chaos Expansion (PCE), express log-likelihood in a PCE basis and obtain a new posterior PCE.
Main IDEA is to update not probability density, but basis coefficients.
Rao-Blackwellisation schemes for accelerating Metropolis-Hastings algorithmsChristian Robert
Aggregate of three different papers on Rao-Blackwellisation, from Casella & Robert (1996), to Douc & Robert (2010), to Banterle et al. (2015), presented during an OxWaSP workshop on MCMC methods, Warwick, Nov 20, 2015
The generation of Gaussian random fields over a physical domain is a challenging problem in computational mathematics, especially when the correlation length is short and the field is rough. The traditional approach is to make use of a truncated Karhunen-Loeve (KL) expansion, but the generation of even a single realisation of the field may then be effectively beyond reach (especially for 3-dimensional domains) if the need is to obtain an expected L2 error of say 5%, because of the potentially very slow convergence of the KL expansion. In this talk, based on joint work with Ivan Graham, Frances Kuo, Dirk Nuyens, and Rob Scheichl, a completely different approach is used, in which the field is initially generated at a regular grid on a 2- or 3-dimensional rectangle that contains the physical domain, and then possibly interpolated to obtain the field at other points. In that case there is no need for any truncation. Rather the main problem becomes the factorisation of a large dense matrix. For this we use circulant embedding and FFT ideas. Quasi-Monte Carlo integration is then used to evaluate the expected value of some functional of the finite-element solution of an elliptic PDE with a random field as input.
To give the complete list of Uq(sl2)-actions of the quantum plane, we first obtain the structure of quantum plane automorphisms. Then we introduce some special symbolic matrices to classify the series of actions using the weights. There are uncountably many isomorphism classes of the symmetries. We give the classical limit of the above actions.
Many mathematical models use a large number of poorly-known parameters as inputs. Quantifying the influence of each of these parameters is one of the aims of sensitivity analysis. Global Sensitivity Analysis is an important paradigm for understanding model behavior, characterizing uncertainty, improving model calibration, etc. Inputs’ uncertainty is modeled by a probability distribution. There exist various measures built in that paradigm. This tutorial focuses on the so-called Sobol’ indices, based on functional variance analysis. Estimation procedures will be presented, and the choice of the designs of experiments these procedures are based on will be discussed. As Sobol’ indices have no clear interpretation in the presence of statistical dependences between inputs, it also seems promising to measure sensitivity with Shapley effects, based on the notion of Shapley value, which is a solution concept in cooperative game theory.
Rao-Blackwellisation schemes for accelerating Metropolis-Hastings algorithmsChristian Robert
Aggregate of three different papers on Rao-Blackwellisation, from Casella & Robert (1996), to Douc & Robert (2010), to Banterle et al. (2015), presented during an OxWaSP workshop on MCMC methods, Warwick, Nov 20, 2015
The generation of Gaussian random fields over a physical domain is a challenging problem in computational mathematics, especially when the correlation length is short and the field is rough. The traditional approach is to make use of a truncated Karhunen-Loeve (KL) expansion, but the generation of even a single realisation of the field may then be effectively beyond reach (especially for 3-dimensional domains) if the need is to obtain an expected L2 error of say 5%, because of the potentially very slow convergence of the KL expansion. In this talk, based on joint work with Ivan Graham, Frances Kuo, Dirk Nuyens, and Rob Scheichl, a completely different approach is used, in which the field is initially generated at a regular grid on a 2- or 3-dimensional rectangle that contains the physical domain, and then possibly interpolated to obtain the field at other points. In that case there is no need for any truncation. Rather the main problem becomes the factorisation of a large dense matrix. For this we use circulant embedding and FFT ideas. Quasi-Monte Carlo integration is then used to evaluate the expected value of some functional of the finite-element solution of an elliptic PDE with a random field as input.
To give the complete list of Uq(sl2)-actions of the quantum plane, we first obtain the structure of quantum plane automorphisms. Then we introduce some special symbolic matrices to classify the series of actions using the weights. There are uncountably many isomorphism classes of the symmetries. We give the classical limit of the above actions.
Many mathematical models use a large number of poorly-known parameters as inputs. Quantifying the influence of each of these parameters is one of the aims of sensitivity analysis. Global Sensitivity Analysis is an important paradigm for understanding model behavior, characterizing uncertainty, improving model calibration, etc. Inputs’ uncertainty is modeled by a probability distribution. There exist various measures built in that paradigm. This tutorial focuses on the so-called Sobol’ indices, based on functional variance analysis. Estimation procedures will be presented, and the choice of the designs of experiments these procedures are based on will be discussed. As Sobol’ indices have no clear interpretation in the presence of statistical dependences between inputs, it also seems promising to measure sensitivity with Shapley effects, based on the notion of Shapley value, which is a solution concept in cooperative game theory.
This talk is going to be centered on two papers that are going to appear in the following months:
Neerja Mhaskar and Michael Soltys, Non-repetitive strings over alphabet lists
to appear in WALCOM, February 2015.
Neerja Mhaskar and Michael Soltys, String Shuffle: Circuits and Graphs
to appear in the Journal of Discrete Algorithms, January 2015.
Visit http://soltys.cs.csuci.edu for more details (these two papers are number 3 and 19 on the page), as well as Python programs that can be used to illustrate the ideas in the papers. We are going to introduce some basic concepts related to computations on string, present some recent results, and propose two open problems.
Fair ranking in competitive bidding procurement: a case analysisMichael Soltys
Fair and transparent procurement procedures are a cornerstone of a well functioning free-market economy. In particular, bidding is a mechanism whereby companies compete for contracts; when functioning well, the process rewards both the quality of the proposal, and the “reasonableness” of the quote.
Thue showed that there exist arbitrarily long square-free strings over an alphabet of three symbols (not true for two symbols). An open problem was posed, which is a generalization of Thue’s original result: given an alphabet list L = L1, . . . , Ln, where |Li| = 3, is it always possible to find a square-free string, w = w1w2 . . . wn, where wi ∈ Li? In this paper we show that squares can be forced on square-free strings over alphabet lists iff a suffix of the square-free string conforms to a pattern which we term as an offending suffix. We also prove properties of offending suffixes. However, the problem remains tantalizingly open.
This is a three part talk, where I give some historical context to computer science, then do a pitch for the field (from the point of view of prospective students), and then I talk about my three different research threads (proof complexity of linear algebra, 0-1 combinatorial matrices, string algorithms), and finish with a talk about security - where I mostly do consulting work.
I am Ben R. I am a Statistics Assignment Expert at statisticshomeworkhelper.com. I hold a Ph.D. in Statistics, from University of Denver, USA. I have been helping students with their homework for the past 5 years. I solve assignments related to Statistics.
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International Conference on Monte Carlo techniques
Closing conference of thematic cycle
Paris July 5-8th 2016
Campus les cordeliers
Jere Koskela's slides
I am Theofanis A. I am a Maths Assignment Expert at mathsassignmenthelp.com. I hold a Master's in Mathematics from the University of Cambridge. I have been helping students with their assignments for the past 12 years. I solve assignments related to Maths.
Visit mathsassignmenthelp.com or email info@mathsassignmenthelp.com.
You can also call +1 678 648 4277 for any assistance with Maths Assignments.
Random Matrix Theory and Machine Learning - Part 3Fabian Pedregosa
ICML 2021 tutorial on random matrix theory and machine learning.
Part 3 covers: 1. Motivation: Average-case versus worst-case in high dimensions 2. Algorithm halting times (runtimes) 3. Outlook
All of material inside is un-licence, kindly use it for educational only but please do not to commercialize it.
Based on 'ilman nafi'an, hopefully this file beneficially for you.
Thank you.
GraphRAG is All You need? LLM & Knowledge GraphGuy Korland
Guy Korland, CEO and Co-founder of FalkorDB, will review two articles on the integration of language models with knowledge graphs.
1. Unifying Large Language Models and Knowledge Graphs: A Roadmap.
https://arxiv.org/abs/2306.08302
2. Microsoft Research's GraphRAG paper and a review paper on various uses of knowledge graphs:
https://www.microsoft.com/en-us/research/blog/graphrag-unlocking-llm-discovery-on-narrative-private-data/
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Welcome to UiPath Test Automation using UiPath Test Suite series part 3. In this session, we will cover desktop automation along with UI automation.
Topics covered:
UI automation Introduction,
UI automation Sample
Desktop automation flow
Pradeep Chinnala, Senior Consultant Automation Developer @WonderBotz and UiPath MVP
Deepak Rai, Automation Practice Lead, Boundaryless Group and UiPath MVP
Software Delivery At the Speed of AI: Inflectra Invests In AI-Powered QualityInflectra
In this insightful webinar, Inflectra explores how artificial intelligence (AI) is transforming software development and testing. Discover how AI-powered tools are revolutionizing every stage of the software development lifecycle (SDLC), from design and prototyping to testing, deployment, and monitoring.
Learn about:
• The Future of Testing: How AI is shifting testing towards verification, analysis, and higher-level skills, while reducing repetitive tasks.
• Test Automation: How AI-powered test case generation, optimization, and self-healing tests are making testing more efficient and effective.
• Visual Testing: Explore the emerging capabilities of AI in visual testing and how it's set to revolutionize UI verification.
• Inflectra's AI Solutions: See demonstrations of Inflectra's cutting-edge AI tools like the ChatGPT plugin and Azure Open AI platform, designed to streamline your testing process.
Whether you're a developer, tester, or QA professional, this webinar will give you valuable insights into how AI is shaping the future of software delivery.
Smart TV Buyer Insights Survey 2024 by 91mobiles.pdf91mobiles
91mobiles recently conducted a Smart TV Buyer Insights Survey in which we asked over 3,000 respondents about the TV they own, aspects they look at on a new TV, and their TV buying preferences.
The Art of the Pitch: WordPress Relationships and SalesLaura Byrne
Clients don’t know what they don’t know. What web solutions are right for them? How does WordPress come into the picture? How do you make sure you understand scope and timeline? What do you do if sometime changes?
All these questions and more will be explored as we talk about matching clients’ needs with what your agency offers without pulling teeth or pulling your hair out. Practical tips, and strategies for successful relationship building that leads to closing the deal.
Builder.ai Founder Sachin Dev Duggal's Strategic Approach to Create an Innova...Ramesh Iyer
In today's fast-changing business world, Companies that adapt and embrace new ideas often need help to keep up with the competition. However, fostering a culture of innovation takes much work. It takes vision, leadership and willingness to take risks in the right proportion. Sachin Dev Duggal, co-founder of Builder.ai, has perfected the art of this balance, creating a company culture where creativity and growth are nurtured at each stage.
LF Energy Webinar: Electrical Grid Modelling and Simulation Through PowSyBl -...DanBrown980551
Do you want to learn how to model and simulate an electrical network from scratch in under an hour?
Then welcome to this PowSyBl workshop, hosted by Rte, the French Transmission System Operator (TSO)!
During the webinar, you will discover the PowSyBl ecosystem as well as handle and study an electrical network through an interactive Python notebook.
PowSyBl is an open source project hosted by LF Energy, which offers a comprehensive set of features for electrical grid modelling and simulation. Among other advanced features, PowSyBl provides:
- A fully editable and extendable library for grid component modelling;
- Visualization tools to display your network;
- Grid simulation tools, such as power flows, security analyses (with or without remedial actions) and sensitivity analyses;
The framework is mostly written in Java, with a Python binding so that Python developers can access PowSyBl functionalities as well.
What you will learn during the webinar:
- For beginners: discover PowSyBl's functionalities through a quick general presentation and the notebook, without needing any expert coding skills;
- For advanced developers: master the skills to efficiently apply PowSyBl functionalities to your real-world scenarios.
Essentials of Automations: Optimizing FME Workflows with ParametersSafe Software
Are you looking to streamline your workflows and boost your projects’ efficiency? Do you find yourself searching for ways to add flexibility and control over your FME workflows? If so, you’re in the right place.
Join us for an insightful dive into the world of FME parameters, a critical element in optimizing workflow efficiency. This webinar marks the beginning of our three-part “Essentials of Automation” series. This first webinar is designed to equip you with the knowledge and skills to utilize parameters effectively: enhancing the flexibility, maintainability, and user control of your FME projects.
Here’s what you’ll gain:
- Essentials of FME Parameters: Understand the pivotal role of parameters, including Reader/Writer, Transformer, User, and FME Flow categories. Discover how they are the key to unlocking automation and optimization within your workflows.
- Practical Applications in FME Form: Delve into key user parameter types including choice, connections, and file URLs. Allow users to control how a workflow runs, making your workflows more reusable. Learn to import values and deliver the best user experience for your workflows while enhancing accuracy.
- Optimization Strategies in FME Flow: Explore the creation and strategic deployment of parameters in FME Flow, including the use of deployment and geometry parameters, to maximize workflow efficiency.
- Pro Tips for Success: Gain insights on parameterizing connections and leveraging new features like Conditional Visibility for clarity and simplicity.
We’ll wrap up with a glimpse into future webinars, followed by a Q&A session to address your specific questions surrounding this topic.
Don’t miss this opportunity to elevate your FME expertise and drive your projects to new heights of efficiency.
Transcript: Selling digital books in 2024: Insights from industry leaders - T...BookNet Canada
The publishing industry has been selling digital audiobooks and ebooks for over a decade and has found its groove. What’s changed? What has stayed the same? Where do we go from here? Join a group of leading sales peers from across the industry for a conversation about the lessons learned since the popularization of digital books, best practices, digital book supply chain management, and more.
Link to video recording: https://bnctechforum.ca/sessions/selling-digital-books-in-2024-insights-from-industry-leaders/
Presented by BookNet Canada on May 28, 2024, with support from the Department of Canadian Heritage.
Epistemic Interaction - tuning interfaces to provide information for AI supportAlan Dix
Paper presented at SYNERGY workshop at AVI 2024, Genoa, Italy. 3rd June 2024
https://alandix.com/academic/papers/synergy2024-epistemic/
As machine learning integrates deeper into human-computer interactions, the concept of epistemic interaction emerges, aiming to refine these interactions to enhance system adaptability. This approach encourages minor, intentional adjustments in user behaviour to enrich the data available for system learning. This paper introduces epistemic interaction within the context of human-system communication, illustrating how deliberate interaction design can improve system understanding and adaptation. Through concrete examples, we demonstrate the potential of epistemic interaction to significantly advance human-computer interaction by leveraging intuitive human communication strategies to inform system design and functionality, offering a novel pathway for enriching user-system engagements.
Generating a custom Ruby SDK for your web service or Rails API using Smithyg2nightmarescribd
Have you ever wanted a Ruby client API to communicate with your web service? Smithy is a protocol-agnostic language for defining services and SDKs. Smithy Ruby is an implementation of Smithy that generates a Ruby SDK using a Smithy model. In this talk, we will explore Smithy and Smithy Ruby to learn how to generate custom feature-rich SDKs that can communicate with any web service, such as a Rails JSON API.
7. Quantified Permutation Frege 7
Haj´os Calculus
Axiom: K4 t
t
t
t
d
dd
Addition Rule: Add any number of vertices and/or edges.
Join Rule:
t
t
t
t
d
dd t
t
t
t
d
dd
=⇒
t
t
t
tt
t
ttj1 j2
j1 j2
i1
i
i2
d
dd
Contraction Rule: Contract two nonadjacent vertices into a
single vertex, and remove the resulting duplicated edges.
8. Quantified Permutation Frege 8
We can express k-colorability of graphs in ∃PLA.
Let 0i denote the i × i matrix of zeros.
Let G be a graph, and AG its adjacency matrix. We can state that
G is k-colorable, for any fixed k, as follows:
(∃P)(∃i1, i2, . . . , ik)
bounded by size of AG
[PAGPt
=
0i1 ∗ · · · ∗
∗ 0i2 · · · ∗
...
...
...
...
∗ ∗ ∗ 0ik
]
Let non3col(X) be the negation of this formula with k = 3.
Let HC(X, Y ) be the (LA) formula stating that Y is a HC
derivation of X.
Theorem: ∀PLA HC(X, Y ) → non3col(X).
9. Quantified Permutation Frege 9
• ∀PLA HC(X, Y ) → non3col(X)
• H∗
1 p(|σ|) HC(X, Y ) → non3col(X) σ and so
H∗
1 p(|ˆσ|) HC( G¬S , π ) ˆσ → non3col( G¬S ) ˆσ.
• H∗
1 p(|ˆσ|) non3col( G¬S ) ˆσ → S
11. Steinitz Exchange Lemma 11
We encode a set of vectors {v1, v2, . . . , vn} as a matrix
T = [v1v2 . . . vn].
Steinitz Exchange Theorem (SET): if T is total, and E is
linearly independent, then there exists F ⊆ T, such that |F| = |E|,
and (T − F) ∪ E is total.
∃X, TX = I ∧ (∀Y = 0, EY = 0) → ∃F ⊆ T, |F| = |E| ∧ ∃X, (T − F ∪ E)X = I
So SET is a ΠB
2 formulas of QLA.
12. Steinitz Exchange Lemma 12
Given T, E, the matrix F can be computed in NC2
.
Suppose E = [e1e2] and T = [t1t2t3t4], then consider
[e1e2] [e1e2t1] [e1e2t1t2] [e1e2t1t2t3] [e1e2t1t2t3t4]
Independently for every i = 0, 1, 2, 3, if
rank([e1e2t1 . . . ti]) = rank([e1e2t1 . . . ti+1])
then put ti+1 in F.
Rank can be computed in NC2
with Mulmuley’s algorithm.
13. Steinitz Exchange Lemma 13
Mulmuley’s Algorithma
M is n × n matrix, pM (x) its char. poly. (Berkowitz’s alg.)
Geometric Rank : usual rank.
Algebraic Rank : n − (highest power of x that divides pM (x)).
Claim: RankG(M) = RankG(M2
) ⇒ RankG(M) = RankA(M).
Given M, let M be
0 Mt
M 0
Clearly, rankG(M) = 1
2 rankG(M ).
M = M · diag(1, y, y2
, . . . , y2n−1
); rankG(M ) = rankG((M )2
).
Here y is an indeterminate, and M is a matrix over the field F(y).
aParallel Linear Algebra, by Joachim von zur Gathen, chapter in Synthesis
of Parallel Algorithms.
14. Steinitz Exchange Lemma 14
Mulmuley’s Algorithma
M is n × n matrix, pM (x) its char. poly. (Berkowitz’s alg.)
Geometric Rank : usual rank.
Algebraic Rank : n − (highest power of x that divides pM (x)).
Claim: RankG(M) = RankG(M2
) ⇒ RankG(M) = RankA(M).
Given M, let M be
0 Mt
M 0
Clearly, rankG(M) = 1
2 rankG(M ).
M = M · diag(1, y, y2
, . . . , y2n−1
); rankG(M ) = rankG((M )2
).
Here y is an indeterminate, and M is a matrix over the field F(y).
aParallel Linear Algebra, by Joachim von zur Gathen, chapter in Synthesis
of Parallel Algorithms.
15. Steinitz Exchange Lemma 15
Mulmuley’s Algorithma
M is n × n matrix, pM (x) its char. poly. (Berkowitz’s alg.)
Geometric Rank : usual rank.
Algebraic Rank : n − (highest power of x that divides pM (x)).
Claim: RankG(M) = RankG(M2
) ⇒ RankG(M) = RankA(M).
Given M, let M be
0 Mt
M 0
Clearly, rankG(M) = 1
2 rankG(M ).
M = M · diag(1, y, y2
, . . . , y2n−1
); rankG(M ) = rankG((M )2
).
Here y is an indeterminate, and M is a matrix over the field F(y).
aParallel Linear Algebra, by Joachim von zur Gathen, chapter in Synthesis
of Parallel Algorithms.
16. Steinitz Exchange Lemma 16
Mulmuley’s Algorithma
M is n × n matrix, pM (x) its char. poly. (Berkowitz’s alg.)
Geometric Rank : usual rank.
Algebraic Rank : n − (highest power of x that divides pM (x)).
Claim: RankG(M) = RankG(M2
) ⇒ RankG(M) = RankA(M).
Given M, let M be
0 Mt
M 0
Clearly, rankG(M) = 1
2 rankG(M ).
M = M · diag(1, y, y2
, . . . , y2n−1
); rankG(M ) = rankG((M )2
).
y is an indeterminate, and M is a matrix over the field F(y).
aParallel Linear Algebra, by Joachim von zur Gathen, chapter in Synthesis
of Parallel Algorithms.
17. Steinitz Exchange Lemma 17
SET can be shown with PolyTime concepts.
Can it be shown with NC2
concepts?
18. Steinitz Exchange Lemma 18
SET proves in QLA the following principles
1. (∃B = 0)[AB = I ∨ AB = 0],
2. The columns of an n × (n + 1) matrix are linearly dependent,
3. Every matrix has an annihilating polynomial,
4. AB = I ⊃ BA = I,
5. Existence of An
, and the Cayley-Hamilton Thm.
19. Steinitz Exchange Lemma 19
QLA can prove the existence of powers of a matrix from SET.
Let POW(A, n) be the formula:
∃ X0X1 . . . Xn (∀i ≤ n)[X0 = I ∧ (i n ⊃ Xi+1 = Xi ∗ A)]
Show QLA (∃B = 0)[AB = I ∨ AB = 0] ⊃ POW(A, n).
20. Steinitz Exchange Lemma 20
Let N be the n2
× n2
matrix consisting of n × n blocks which are all
zero except for (n − 1) copies of A above the diagonal zero blocksa
.
Then Nn
= 0, and (I − N)−1
= I + N + N2
+ . . . + Nn−1
=
I A A2
. . . An−1
0 I A . . . An−2
...
...
...
0 0 0 . . . I
.
Set C = I − N.
Show that if CB = 0, then B = 0, using induction on the rows of
B, starting with the bottom row.
Using (∃B = 0)[CB = I ∨ CB = 0], conclude that there is a B such
that CB = I.
aA taxonomy of problems with fast parallel algorithms, by Stephen Cook.
21. Steinitz Exchange Lemma 21
Let N be the n2
× n2
matrix consisting of n × n blocks which are all
zero except for (n − 1) copies of A above the diagonal zero blocksa
.
Then Nn
= 0, and (I − N)−1
= I + N + N2
+ . . . + Nn−1
=
I A A2
. . . An−1
0 I A . . . An−2
...
...
...
0 0 0 . . . I
.
Set C = I − N.
Show that if CB = 0, then B = 0, using induction on the rows of
B, starting with the bottom row.
Using (∃B = 0)[CB = I ∨ CB = 0], conclude that there is a B such
that CB = I.
aA taxonomy of problems with fast parallel algorithms, by Stephen Cook.
22. Steinitz Exchange Lemma 22
Let N be the n2
× n2
matrix consisting of n × n blocks which are all
zero except for (n − 1) copies of A above the diagonal zero blocksa
.
Then Nn
= 0, and (I − N)−1
= I + N + N2
+ . . . + Nn−1
=
I A A2
. . . An−1
0 I A . . . An−2
...
...
...
0 0 0 . . . I
.
Set C = I − N.
Show that if CB = 0, then B = 0, using induction on the rows of
B, starting with the bottom row.
Using (∃B = 0)[CB = I ∨ CB = 0], conclude that there is a B such
that CB = I.
aA taxonomy of problems with fast parallel algorithms, by Stephen Cook.
23. Steinitz Exchange Lemma 23
Let N be the n2
× n2
matrix consisting of n × n blocks which are all
zero except for (n − 1) copies of A above the diagonal zero blocksa
.
Then Nn
= 0, and (I − N)−1
= I + N + N2
+ . . . + Nn−1
=
I A A2
. . . An−1
0 I A . . . An−2
...
...
...
0 0 0 . . . I
.
Set C = I − N.
Show that if CB = 0, then B = 0, using induction on the rows of
B, starting with the bottom row.
Using (∃B = 0)[CB = I ∨ CB = 0], conclude that there is a B such
that CB = I. Finally, show that B = I + N + N2
+ · · · + Nn−1
.
aA taxonomy of problems with fast parallel algorithms, by Stephen Cook.
24. Steinitz Exchange Lemma 24
Strong Linear Independence (SLI)
if {v1, . . . , vm} are n × 1, non-zero, linearly dependent vectors, then
there exists a 1 ≤ k m such that
{
lin. indep.
v1, . . . , vk, vk+1
lin. dep.
, vk+2, . . . , vm}
25. Steinitz Exchange Lemma 25
Csanky’s algorithm (NC2
) for computing the characteristic poly. of
a matrix uses
’s
symmetric polynomials:
s0 = 1,
sk =
1
k
k
i=1
(−1)i−1
sk−itr(Ai
)
pA(x) := s0xn
− s1xn−1
+ s2xn−2
− · · · ± snx0
.
26. Steinitz Exchange Lemma 26
Theorem: QLA proves the Cayley-Hamilton Thm. from SET
and SLI.
The 12 steps proof :
(1) pA is the characteristic polynomial of the matrix A as
computed by Csanky’s algorithm.
(2) Let W = {ei, Aei, . . . , An
ei}.
(3) By SET, W must be linearly dependent.
(4) By SLI there exists a k ≤ n such that
W0 = {ei, Aei, . . . , Ak−1
ei} is linearly independnet and k is the
largest such index.
27. Steinitz Exchange Lemma 27
(5) Ak
ei can be written as a linear combination of the vectors in
W0.
Let c1, . . . , ck be the coefficients of this linear combination, so that
if g(x) = xk
+ c1xk−1
+ · · · + ck, then g(A)ei = 0.
(6) Let Ag be the k × k companion matrix of g,
0 0 0 . . . 0 −ck
1 0 0 . . . 0 −ck−1
0 1 0 . . . 0 −ck−2
...
...
...
0 0 0 . . . 1 −c1
28. Steinitz Exchange Lemma 28
(7) LAP proves pAg = g, and so LAP proves (pAg (A))ei = 0.
(8) Extend W0 to B = W0 ∪ {ej1 , . . . , ejn−k
}.
Existence of B follows from SET:
let T = B0 = the standard basis,
let E = W0, which is linearly independent,
let F = B0 − {ej1 , . . . , ejn−k
},
so B = (T − F) ∪ E.
A ∼
Ag E1
0 E2
29. Steinitz Exchange Lemma 29
(9) LAP proves that if C1 ∼ C2 then pC1 (x) = pC2 (x)
(tr(A) = tr(PAP−1
), since tr(AB) = tr(BA)).
(10) LAP proves that if
C =
C1 ∗
0 C2
then pC(x) = pC1 (x) · pC2 (x).
(11) ∴ pA(A)ei = (pAg (A) · pE(A))ei = pE(A) · (pAg (A)ei) = 0.
(12) This is true for all ei in the standard basis, and so pA(A) = 0.
32. Clow Sequences 32
A clowa
(closed walk) is a walk (w1, . . . , wl) starting from vertex w1
and ending at the same vertex, where any (wi, wi+1) is an edge in
the graph.
Vertex w1 is the least-numbered vertex in the clow, and it is called
the head of the clow. We also require that the head occur only once
in the clow. This means that there is exactly one incoming edge
(wl, w1) and one outgoing edge (w1, w2) at w1.
A clow sequence is a sequence of clows (C1, . . . , Ck) with two
properties: (i) the sequence is ordered by heads:
head(C1) . . . head(Ck)
and (ii) the total number of edges, counted with multiplicity, adds
to n.
aDeterminant: Combinatorics, Algorithms, and Complexity, by M. Mahajan
and V. Vinay.
34. Clow Sequences 34
det(A) =
C is a
clow sequence
sign(C)w(C)
=
C is a
clow sequence
with head of 1st clow 1
sgn(C)w(C)
=
C is a
clow sequence
with prefix property
sgn(C)w(C)
C = (C1, . . . , Ck) has the prefix property if ∀i k the total length
of C1, . . . , Ci−1 is at least head(Ci) − 1.
35. Clow Sequences 35
det(A) =
C is a
clow sequence
sign(C)w(C)
=
C is a
clow sequence
with head of 1st clow 1
sgn(C)w(C)
=
C is a
clow sequence
with prefix property
sgn(C)w(C)
C = (C1, . . . , Ck) has the prefix property if ∀i k the total length
of C1, . . . , Ci−1 is at least head(Ci) − 1.
36. Clow Sequences 36
det(A) =
C is a
clow sequence
sign(C)w(C)
=
C is a
clow sequence
with head of 1st clow 1
sgn(C)w(C)
=
C is a
clow sequence
with prefix property
sgn(C)w(C)
C = (C1, . . . , Ck) has the prefix property if ∀i k the total length
of C1, . . . , Ci−1 is at least head(Ci) − 1.
37. Clow Sequences 37
det(A) =
C is a
clow sequence
sign(C)w(C)
=
C is a
clow sequence
with head of 1st clow 1
sgn(C)w(C)
=
C is a
clow sequence
with prefix property
sgn(C)w(C)
C = (C1, . . . , Ck) has the prefix property if ∀i k the total length
of C1, . . . , Ci−1 is at least head(Ci) − 1.
38. Clow Sequences 38
det(A) =
C is a
clow sequence
sign(C)w(C)
=
C is a
clow sequence
with head of 1st clow 1
sgn(C)w(C)
=
C is a
clow sequence
with prefix property
sgn(C)w(C)
C = (C1, . . . , Ck) has the prefix property if ∀i k the total length
of C1, . . . , Ci−1 is at least head(Ci) − 1.
39. Clow Sequences 39
A is n × n.
Define layered, directed, acyclic graph HA with three special
vertices: s, t+, t−
such that
det(A) =
ρ:s;t+
w(ρ) −
ρ:s;t−
w(ρ)
weight of path ρ is the product of weights of the edges appearing
on it.
Main Idea: s ; t+ (s ; t−) paths will be in 1-1 correspondence
with clow sequences of positive (negative) sign.
40. Clow Sequences 40
Vertices of HA: {s, t+, t−} together with
{[p, h, u, i] : p ∈ {0, 1} (parity), h, u ∈ [n], 0 ≤ i ≤ n − 1}
Meaning of the vertices: if a path ρ (starting from s) reaches a
vertex [p, h, u, i], this indicates that in the clow sequence being
constructed along this path:
• p is the parity of the quantity “n+(the number of components
already constructed),”
• h is the head of the clow currently being constructed,
• u is the vertex that the current clow has reached,
• and i is the number of edges traversed so far (in this and
preceding clows).
Finally, a path from s to t+ (t−) corresponds to a clow sequence of
positive (negative) parity.
41. Clow Sequences 41
The edges of HA:
Edge Condition Weight
(s, [b, h, h, 0]) h ∈ [n] and b = parity of n 1
([p, h, u, i] , [p, h, v, (i + 1)]) v h and (i + 1) n auv
([p, h, u, i] , [¯p, h , h , (i + 1)]) h h and (i + 1) n auh
([1, h, u, (n − 1)] , t+) auh
([0, h, u, (n − 1)] , t−) auh
43. Clow Sequences 43
For u, v, i ∈ [n] and p ∈ {0, 1} (Initialize values to 0)
V [p, u, v, (i − 1)] ← 0
V [t+] ← 0 and V [t−] ← 0
b ← parity of n
For u ∈ [n] (Set selected values at layer 0 to 1)
V [b, u, u, 0] ← 1
For i = 0 to (n − 2) (Process outgoing edges from each layer)
For u, v ∈ [n] such that u ≤ v and p ∈ {0, 1}
For w ∈ {u + 1, . . . , n}
V [p, u, w, (i + 1)] ← V [p, u, w, (i + 1)] + V [p, u, v, i] · avw
V [¯p, w, w, (i + 1)] ← V [¯p, w, w, (i + 1)] + V [p, u, v, i] · avu
For u, v ∈ [n] such that u ≤ v and p ∈ {0, 1}
V [t+] ← V [t+] + V [1, u, v, (n − 1)] · avu
V [t−] ← V [t−] + V [0, u, v, (n − 1)] · avu
Return V [t+] − V [t−]
44. Clow Sequences 44
• Running time: O(n4
)-many edges in HA, and one addition and
one multiplication per edge.
• Space: at each stage only the values of two adjacent layers are
required, so O(n2
) entries; each N many bits.
• To compute (pA)i, we sum over clow sequences of (n − i) many
edges: add ti
+, ti
−, for each i, and connect ti
+, ti
− to the
(n − i)-th layer.
• If V (ti
+) − V (ti
−) = 0, then i ≤ rankA, and rankA ≤ rankG, we
can conclude that the matrix has rank at least i.
45. Clow Sequences 45
• Pruning of HA: paths going through vertices of the form
[p, h, u, i] with h i + 1
cannot correspond to cycle covers (once h becomes a head, at
least (h − 1) edges should have been visited in the preceding
cycle).
• Prefix Property: Extend the prefix property to all the
coefficients,
(pA)i = (−1)n−i
C is an
(n − i)-clow sequence
with prefix property
sgn(C)w(C)
• Berkowitz’s algorithm computes over clows with the prefix
property . . .