In 2008, November 23-28, the workshop of "Classical Problems on Planar Polynomial Vector Fields " was held in the Banff International Research Station, Canada. Called "classical problems", it was concerned with the following: (1) Problems on integrability of planar polynomial vector fields. (2) The problem of the center stated by Poincare for real polynomial differential systems, which asks us to recognize when a planar vector field defined by polynomials of degree at most n possesses a singularity which is a center. (3) Global geometry of specific classes of planar polynomial vector fields. (4) Hilbert's 16th problem. These problems had been posed more than 110 years ago. Therefore, they are called "classical problems" in the studies of the theory of dynamical systems. The qualitative theory and stability theory of differential equations, created by Poincare and Lyapunov at the end of the 19th century, had major developments as two branches of the theory of dynamical systems during the 20th century. As a part of the basic theory of nonlinear science, it is one of the very active areas in the new millennium. This book presents in an elementary way the recent significant developments in the qualitative theory of planar dynamical systems. The subjects are covered as follows: the studies of center and isochronous center problems, multiple Hopf bifurcations and local and global bifurcations of the equivariant planar vector fields which concern with Hilbert's 16th problem. The book is intended for graduate students, post-doctors and researchers in dynamical systems. For all engineers who are interested in the theory of dynamical systems, it is also a reasonable reference. It requires a minimum background of a one-year course on nonlinear differential equations.

Polish off your magnifying glass and step into the shoes of your favourite detectives as you unlock tantalising clues and solve intricate puzzles. There are over 100 criminally teasing challenges to be scrutinised, including word searches, anagrams, snapshot covers, and crosswords - a favourite puzzle of crime fiction's golden age. Suitable for all ages and levels, this is the ultimate test for fans of the British Library Crime Classics series. For six years, the British Library have brought neglected crime fiction writers into the spotlight in a series of republished novels and anthologies. There are now more than 50 British Library Crime Classics titles to collect.

Over twenty-five years ago, Nikoli, a Japanese puzzle and game company, started publishing a curious logic puzzle called Sudoku. The result was magical and in recent years, Sudoku has spread from Japan to other countries. These newer puzzles, however, are often computer-generated and lack the simple beauty of handmade puzzles. Nikoli continues to nurture and develop Sudoku with handmade puzzles that contain the vital ingredient that make puzzles enjoyable--the sense of communication between solver and author. The best Sudoku make you concentrate, but aren't stressful.
Arranged from "Easy" to "Very Hard," here are over 300 logic puzzles that celebrate the compulsive joy of Sudoku with symmetry, smartness, and elegance. Absorbing and engaging, every puzzle is designed by an author who anticipates your next step and obscures the path, while never leading you into frustration. Each puzzle carries the careful thought of a master who knows when to encourage and when to withhold, who shares the joy of that moment when one hard-won number is captured and the entire puzzle falls into place.

Planter Perfection 1000 Piece Puzzle with Shaped Pieces from Galison celebrates container planting and the newfound focus on upcycling. This puzzle includes 20 specially shaped pieces for an added challenge. Galison puzzles are packaged in matte-finish sturdy boxes, perfect for gifting, reuse, and storage. * 1000 Piece Puzzle, Random Cut * Puzzle Size: 27 x 20", 686 x 508 mm * Box Size: 11.5 x 8.5 x 2", 292 x 216 x 51 mm, Minimal Puzzle Dust * Includes 20 Shaped Puzzle Pieces * Includes Puzzle Insert * Puzzle greyboard contains 90% recycled paper. Packaging contains 70% recycled paper and is made responsibly from FSC-certified material. Printed with nontoxic inks.

150 Large-Print Word Search Puzzles! Peace of Mind Bible Word Search combines brain-building fun with the truths and promises of scripture. Thanks to large, boldface print, puzzle enthusiasts young and old can enrich their free time finding words from Bible verses that remind us of the freedom we have in Jesus. From freedom from the law of sin (Romans 8:2), meditating on the responsibility of freedom (1 Corinthians 9:19), to reflecting on freedom in the Old Testament (Psalm 119:45), each themed word find is a chance for readers to marinate in scripture while finding satisfaction in solving a puzzle. Keep your brain sharp, your eyes at ease, and your heart full of God's Word! Enjoy 150 word search puzzles based around Biblical themes Highlights some of the most treasured passages and themes of the Bible Large, bold print prevents eye strain while you test your Bible knowledge! Complete answer key included You may find that you're committing each verse to memory as you complete the puzzle! Clean, fun, and just challenging enough, this book is a perfect gift for the puzzler in your life.

Some questions you never think to ask. Others, you didn't know you didn't know. And some facts are so surprising they cry out for answers.

What can a president actually do? Why do cities sink into the ground? Why is Australia seemingly invulnerable to recessions? Why do people in couples do more housework than singletons? The brilliant minds of the Economist collect these questions. Individually, they might seem bite-sized and inconsequential, but taken together they can reveal a whole new world.

You Watch Too Much TV is a Book of Lists for the television generation, offering fun facts and quizzes on Leave It To Beaver, Everybody Loves Raymond, and just about every show in between. Examples of a couple of debate-inspiring questions: Where in the city did Ralph Kramden's upstairs neighbor Ed Norton work on The Honeymooners? In the city's sewers; Who was the first to be voted off the island on the first episode of Survivor? Sonja Christopher

Do you love playing wordle? Do you want to test your skills with a more extreme version of the game? If you do, then you will love this collection of 500 extreme wordle puzzles to do anytime, anywhere. Extreme Wordle Challenge presents a fun, interactive collection of brain-teasing puzzles, that can be played offline and will entertain for hours and hours. These mind-melting puzzles are graded from Intense to Extreme. Puzzlers must guess what the correct word is, deducing from previous words in the grid what letters go where. A clue means there is only one correct solution to each puzzle, and answers can be found at the back of the book. Whether you are looking for puzzle practiceto train your brain, or seeking a screen-free offline alternative to online puzzles, or a wordle challenge like no other, this collection will have you enthralled. Perfect for commuters, keen puzzlers and all ardent wordle fans, and suitable for children and adults, this book is the perfect gift for anyone who can't get enough of the sensation puzzle game and wishes they could do more!

From the bestselling author of 52 Things to Do While You Poo, this nostalgic mix of trivia and puzzles will bring back the awesome appeal of the Eighties If you grew up in the 1980s, you know that nothing compares to the music, fashion, toys, TV, films and sheer feel of that decade. But how much can you really remember? When you next take a trip to the toilet, this colourful collection of puzzles, activities and trivia will serve as a leisurely stroll down memory lane, dusting off half-remembered facts and even filling in a few gaps. From bestselling author and fiendish brain-teaser Hugh Jassburn, this illustrated celebration of history's finest decade includes the following challenges and more: Help Arnie navigate through a jungle maze to get to the chopper Match hit songs to the year they came out Solve trivia questions relating to Madonna and the TV show Dallas Track down the names of iconic world leaders in a word search Spot the differences in a sea of Rubik's cubes 52 Things to Do While You Poo: The 1980s Edition is the perfect gift for those who lived through these glory days - or those who just wish they had.

Recognizing the widespread American Indian belief that you can learn while you play and play while you learn, "Native American Games and Stories" provides young readers with stories and games that educate and entertain them. Illustrations.

Supersized word search fun! Everything is bigger in The Everything Easy Large-Print Word Search Book, Volume 6--the letters, the clues, the grids--and especially the fun! Each of these brand-new puzzles helps you improve vocabulary, memory, and problem-solving skills. With clues ranging from beloved books and classic TV shows to favorite foods and popular vacation spots, these light and easy puzzles are perfect for taking a break--and exercising your mind! Whether you're a beginner or an experienced puzzler, you'll enjoy the satisfaction of quickly solving these entertaining word searches.

Do you know your arsole from your electron? Whether tritium or trivium, this periodically puzzling collection of over 400 different quiz questions, word games and brain teasers will challenge the chemist in you. Drawing on an illustrated cornucopia of chemicals with subjects ranging from the sub-atomic to the astronomic, stories of scientists, their quirks, discoveries, and inventions will delight and inspire you. Journey through tales of how chemistry and other sciences have touched all our lives, from the food we eat to the air that we breathe, from the novels that we read to the movies that we watch. Elementary! is compiled by the Royal Society of Chemistry's puzzler Paul Board, with each chapter concentrating on a particular branch of science or facet of life. Explore scientists and superpowers, particles, places, plants, planets and poisons, and more. Get your thinking cap on!

Kakuro is the next hot puzzle craze, and everyone can give it a try with this new, multilevel series. These language-free number puzzles use pure logic and require just simple arithmetic to solve. So, in addition to being fun, they help develop your powers of deduction and reasoning. Beginners can get started - and more experienced solvers hone their skills - with these perfectly tiered "belt" books, each containing 150 kakuros. They take their cue from the belt colors in martial arts: white is for novices, green for intermediates, brown for very accomplished players, and black for those consummate experts who crave a challenge.

Kakuro is the next hot puzzle craze, and everyone can give it a try with this new, multilevel series. These language-free number puzzles use pure logic and require just simple arithmetic to solve. So, in addition to being fun, they help develop your powers of deduction and reasoning. Beginners can get started - and more experienced solvers hone their skills - with these perfectly tiered "belt" books, each containing 150 kakuros. They take their cue from the belt colors in martial arts: white is for novices, green for intermediates, brown for very accomplished players, and black for those consummate experts who crave a challenge.