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Description
Number Theory: A Very Short IntroductionNumber theory is the branch of mathematics that is primarily concerned with the counting numbers. Of particular importance are the prime numbers, the 'building blocks' of our number system. The subject is an old one, dating back over two millennia to the ancient Greeks, and for many years has been studied for its intrinsic beauty and elegance, not least because several of its challenges are so easy to state that everyone can understand them, and yet
Number theory is the branch of mathematics that is primarily concerned with the counting numbers. Of particular importance are the prime numbers, the 'building blocks' of our number system. The subject is an old one, dating back over two millennia to the ancient Greeks, and for many years has been studied for its intrinsic beauty and elegance, not least because several of its challenges are so easy to state that everyone can understand them, and yet no-one has ever been able to resolve them. But number theory has also recently become of great practical importance - in the area of cryptography, where the security of your credit card, and indeed of the nation's defence, depends on a result concerning prime numbers that dates back to the 18th century. Recent years have witnessed other spectacular developments, such as Andrew Wiles's proof of 'Fermat's last theorem' (unproved for over 250 years) and some exciting work on prime numbers. In this Very Short Introduction Robin Wilson introduces the main areas of classical number theory, both ancient and modern. Drawing on the work of many of the greatest mathematicians of the past, such as Euclid, Fermat, Euler, and Gauss, he situates some of the most interesting and creative problems in the area in their historical context. ABOUT THE SERIES:The Very Short Introductions series from Oxford University Press contains hundreds of titles in almost every subject area. These pocket-sized books are the perfect way to get ahead in a new subject quickly. Our expert authors combine facts, analysis, perspective, new ideas, and enthusiasm to make interesting and challenging topics highly readable.
Binding Type: Paperback
Publisher: Oxford University Press, USA
Published: 08/01/2020
ISBN: 9780198798095
Pages: 176
Weight: 0.30lbs
Size: 6.60h x 4.30w x 0.40d
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4.4 ★★★★★
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Product Reviews
★★★★★ 5
Awesome Cabin Air Filter
Style: BE-151H 1-Pack
This product is not only cost efficient, it was also easy to install. The instructions in the package were helpful. I would definitely recommend using this filter for your 2017 Hyundai Sonata.
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Reviewed in the United States on May 13, 2026
★★★★★ 4
the "fit" is very precise
Style: BE-176H 1-Pack
Nice Fabrication, Good materials, perfect adhesive applications, "clean joints" etc.
Appears to be a good UPGRADE from the stock Motorcraft product.
CONs: The FIT was a "smidge TIGHT", and took very precise initial alignment and "pressure" to begin to slide into the rectangular hole. I measured the "Hole" at 7.375" wide, or (187.33 mm)... the FILTER is exactly the SAME.
I would suggest maybe reducing the Width by 1 mm, to allow for an easier installation.
The MOTORCRAFT uses an "open-cell" foam structure for the (2) Side pieces on their filter assembly, allowing some "compression to fit", of the Width, easing the difficulty of installation, yet still filling all voids.
In summation, the "fit" is very precise. Not to be hurried or rushed, maybe a bit meticulous for the impatient or weak of heart.
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Reviewed in the United States on April 2, 2025
★★★★★ 5
Great item and Affordable
Style: BE-157H 1-Pack
Perfectly fit for my corolla
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Reviewed in the United States on May 4, 2026
★★★★★ 5
Breathe Easy!
Style: BE-728H 1-Pack
Ladies and gentlemen, buckle up, because we're about to embark on a whirlwind adventure of cleaner air and contortionist-worthy installation feats with the Spearhead HEPA Breathe Easy Cabin Filter!
First off, let's talk about installation. If you're someone who loves a good yoga session or considers themselves a Cirque du Soleil dropout, this is the filter for you. The instructions are so clear and helpful that even a goldfish could follow them. However, be prepared to twist and turn in ways you didn't know your body could. And let me tell you, I'm not in the best of shape. I discovered muscles I never knew I had and positions that would make a pretzel jealous. But don't worry, it's all worth it.
Once installed, my car’s air quality shot up faster than a rocket to Mars. And although my car is old and doesn't have any fancy AI, it felt like it was saying, "Ahh, finally, some quality air!" The air was so crisp and pure, I half expected to see little cartoon birds chirping around my head. And let me emphasize this: the product quality is top-notch. It not only works great but looks good too.
I purchased this gem because my wife has bad allergies, and so far, it's been a game-changer. She hasn't sneezed once, and the car doesn't smell as musty with the air conditioning on. It's like we've been transported to a fresh, alpine air paradise every time we drive.
In summary, the Spearhead HEPA Breathe Easy Cabin Filter is a game-changer. It's as easy to install as putting on socks—if putting on socks required you to become a human origami. But trust me, once it's in place, your lungs will thank you, and your car will feel like it's breathing the fresh, alpine air of the Swiss Alps. Five stars, and a standing ovation from my now incredibly limber body!
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Reviewed in the United States on July 10, 2024
★★★★★ 5
Works a lot better than the previous one.
Style: BE-775H 1-Pack
Great product at a great price. It seemed to fit almost perfect with out having to crunch it in. Highly recommend.
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Reviewed in the United States on March 5, 2026