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Description
Principles and Techniques in Combinatorics"This book should be a must for all mathematicians who are involved in the training of Mathematical Olympiad teams, but it will also be a valuable source of problems for university courses." Mathematical Reviews A textbook suitable for undergraduate courses. The materials are presented very explicitly so that students will find it very easy to read. A wide range of examples, about 500 combinatorial problems taken from various mathematical competitions
"This book should be a must for all mathematicians who are involved in the training of Mathematical Olympiad teams, but it will also be a valuable source of problems for university courses."
Mathematical Reviews
A textbook suitable for undergraduate courses. The materials are presented very explicitly so that students will find it very easy to read. A wide range of examples, about 500 combinatorial problems taken from various mathematical competitions and exercises are also included.
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4.3 ★★★★★
Based on 123 reviews
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Product Reviews
★★★★★ 5
Hallelujah… finally, I found the right pillow!!!
Size: Queen (Pack of 1), Color: White
I have spent a lot of money searching for the right pillow. I recently tried to Tempur-pedic that cost twice with this pillow cost. Tempur-pedic flattened out. I’ve had this pill for a few weeks now and it works wonders. I am a paraplegic. You can have a lot of neck problems. I love the fact that this pillow is adjustable. I immediately saw it was too stuffy and took a bunch out. It works perfect so glad I didn’t spend money on a $200 purple pillow.
I read a lot of reviews and there were a lot of complaints about the odor. Mine did smell funny when it came out of the box. I immediately threw it in the dryer with a few bounce fabric sheets came out smelling fine.
Pillows are a very individual thing, but I think for 40 bucks this pillow is worth a try. I’m really enjoying mine about one of those silk pillowcases to go over it and it sleeps cool and comfortable. Best wishes in your search for the right pillow.
Update: I’ve been using this pillow several months and it continues. Give me a good night rest pain-free.. well worth the money.
UPDATE: I have been using this pillow for three months and it still works great. It does not flat out or get hot..
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Reviewed in the United States on January 29, 2026
★★★★★ 5
Soft comfortable very good pillow
Size: King (Pack of 1), Color: White
I really love my new pillow it's great and comfortable. Yes, it has a little smell, but if you wash the pillowcase and put the pillow on the window for a day you won't notice anything anymore.
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Reviewed in the United States on May 18, 2026
★★★★★ 5
Best place for head
Size: Queen (Pack of 1), Color: White
Do you love not getting sleep and sweating all over your pillow at night when you are asleep? If so then don't buy this pillow! If you want a good nights sleep and cool pillow like me this is the one. Ive always been ehh towards spending so much on a pillow but its 100% worth it, I sleep so much better and it forms to my head and keeps me cool at night. Great support even for my big head and comes with a bag of extra stuffing if you want to have a little more firmer pillow. Highly recommend
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Reviewed in the United States on April 4, 2026
★★★★★ 3
Oversized
Size: Queen (Pack of 2), Color: White
I have chronic neck pain. I am forever buying new pillows. Sometimes I think I found the perfect pillow but then three months later they’re losing their loft. I thought I would give these pillows to try since the stuffing is removable. Now these pillows are really oversized. To the point where I thought that they had sent me king-size pillows but I double checked the packaging and they were Queen. I ended up having to buy king-size pillowcases for them because they just barely fit in the queen size and the pillowcases would always end up pulling back from the edge. So that’s a negative one star there. Now I’ve been sleeping on these pillows for a while and they have held up well. I did end up removing some of the stuffing because it was just too much. I’m a side sleeper and when I use this pillow, it does a good job of keeping my neck in alignment. However, the pillow tends to migrate up as I sleep. Or I tend to slip down off the pillow, either or. So that’s why I’ve removed a second star. Maybe if I removed more stuffing that wouldn’t happen, but then I feel like the loft would be too little. I will say that these provide great support when sitting up in bed reading or watching TV. So would I buy them again? Probably not. Am I going to keep using them? Yes
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Reviewed in the United States on December 23, 2025
★★★★★ 5
Best Pillow Ever
Size: Queen(Pack of 2)
I am absolutely obsessed with these pillows! They have the perfect balance of firmness and softness, providing amazing support for my head and neck. I've never slept better, and I can honestly say I'd order more in a heartbeat. These pillows are a game-changer for my sleep quality. I highly recommend them to anyone looking for the ultimate comfort.
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Reviewed in the United States on May 30, 2026