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Description
Guide to Distribution Theory & Fourier..This important book provides a concise exposition of the basic ideas of the theory of distribution and Fourier transforms and its application to partial differential equations. The author clearly presents the ideas, precise statements of theorems, and explanations of ideas behind the proofs. Methods in which techniques are used in applications are illustrated, and many problems are included. The book also introduces several significant recent topics,
This important book provides a concise exposition of the basic ideas of the theory of distribution and Fourier transforms and its application to partial differential equations. The author clearly presents the ideas, precise statements of theorems, and explanations of ideas behind the proofs. Methods in which techniques are used in applications are illustrated, and many problems are included. The book also introduces several significant recent topics, including pseudodifferential operators, wave front sets, wavelets, and quasicrystals. Background mathematical prerequisites have been kept to a minimum, with only a knowledge of multidimensional calculus and basic complex variables needed to fully understand the concepts in the book.A Guide to Distribution Theory and Fourier Transforms can serve as a textbook for parts of a course on Applied Analysis or Methods of Mathematical Physics, and in fact it is used that way at Cornell.
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4.7 ★★★★★
Based on 80 reviews
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Product Reviews
★★★★★ 4
Just a Toy
This is a snippet from a review I provided for the Ring doorbell...
"The absolute showstopper is the horrific problem with wi-fi - a problem so consistent and acute that it renders this product useless. The doorbell and the cameras are constantly going offline, and the only way that they can be brought back online is for the user to be onsite and physically reconnect the devices. Talk about unclear on the concept! The whole idea of home security is that you want it working when you're AWAY, Amazon, not just when you're at home.
"The slightest network glitch causes the system to completely blow up: a slight power interruption, the router temporarily losing network, etc. However, every single device in my household is smart enough to come back online once the connection has been restored, except...the Ring system. Sometimes, eventually, the doorbell "figures something out" and comes back online, but the cameras? Never. They would be better off as paperweights."
I realize that there are reviews here that claim to offer fixes, but that's not the point. These cameras should behave exactly like any other wi-fi device in the house, bar none - but they don't. The signal in my house is not "weak" - I have repeaters all over the place. I have perfect signal strength on my tablets, phones, laptops, and TVs, yet the Ring software claims that - sometimes - my wi-fi signal is "weak".
Note the emphasis on the word "sometimes". Although the rest of my devices see my wi-fi signal exactly the same wherever they are, these cameras are different. I've seen indicators that have displayed everything from full signal to no signal to everything in between even though the units are positioned in the exact spot every time, no exceptions.
Besides, these reviewers need to read the part I've written here about having to be onsite to bring these units back on line. THIS...is ridiculous.
Last, but certainly not least, these cameras BLEED battery. I've had cases where I've been away a week and the motion detection has never come on and when I get back, the batteries are almost gone. This is less of an issue when the cameras have gone offline, of course, but then what's the point of having a camera with some battery left if it was never working in the first place?
If there is a way around all this, I'd like to know it, but it should come from Amazon - the vendor, not from product reviewers.
UPDATE 8-20-2023: After some great help from a customer service rep (including a replacement door chime), preliminary tests have shown that the cameras now stay online. Of course, only a long-run evaluation will do, but it does seem like things have improved.
At issue was a phemomenon called "node hopping" where the cameras seem to randomly seek out other IP addresses on the subnet then attempt to reconnect. Usually node hopping occurs when there are more devices attached to a subnet that what a router is configured to handle, but in my case, even when all my devices are attached, there are plenty of leftover addresses for the cameras to use. This is especially true when we are away where as many as six devices are actually removed from the network.
With my new Chime Pro, however, that doubles as a subrouter, the cameras are linked to this device exclusively, so node hopping is supposed to cease.
The other issue I had was due to the unusual battery drain on the cameras that I noticed when they are not active and recording. I had not anticipated that they have to remain "alive" for the user so that user can wake them up when needed, or that they wake themselves up when motion is detected. Evidently, this process requires more battery power than I had first believed. Lesson learned is that unless you want to disconnect the cameras and remove the batteries after each use, then be prepared to make sure they are fully charged up before you go away even if they have been little used previously.
Thanks again to Melissa for the support and I hope that other folks can benefit from this information.
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Reviewed in the United States on August 6, 2023
★★★★★ 5
Perfect Solution for Areas Without Electricity – Easy, Reliable, and Worth It
Size: 1 Camera, Size: 1 Camera
I have to admit, this camera brand has become my favorite. This is already my third device: I have a Ring doorbell, a wall-mounted camera, and now this battery-powered version, which turned out to be exactly what I needed for an area where I don't have access to electricity.
I installed it in the hallway of my apartment, right outside the bathroom and bedroom entrances, where there are no outlets, and it has worked perfectly for monitoring that space. It gives me great peace of mind knowing that this area is covered without having to do any complicated installations.
One of the things I like most about this brand is the image and audio quality. The image is clear both day and night, and the sound is crisp, which makes a huge difference in daily use.
The installation was quick and easy, and the app is very user-friendly. Motion notifications arrive instantly, allowing me to stay informed at all times.
It's been installed for about 15 days and the battery is around 53%, which means it will last about a month depending on usage and the amount of motion it detects.
I'm also taking advantage of the 30-day free trial, and what I find excellent is that my current $9.99 plan covers all my devices at no extra cost.It also features two-way audio, integrates seamlessly with Alexa, and has performed well so far, even outdoors.
The only thing I'd mention is that battery life is highly dependent on activity, so in busy areas it may require more frequent recharging.
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Reviewed in the United States on April 10, 2026
★★★★★ 5
Stop thinking about which 1, get these!
Size: 1 Camera
Should have got these along time ago. Procrastinating way too much. Great quality, wireless, long lasting battery thus far. Easy to install just about anywhere. Can be moved around. Great set I bought 2 of the covers front of the house and rear yard plus my doorbell. Security surveillance all around! Dont think twice you'll be more than satisfied and greatful.just probably upset you didnt get them sooner.
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Reviewed in the United States on May 9, 2026
★★★★★ 5
Great security features.
Size: 1 Camera
Works great I just wish the battery last longer.Nightvision is great as well weather proof.Sticks up and is sturdy as well.
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Reviewed in the United States on May 20, 2026
★★★★★ 5
Great Product
Size: 1 Camera
Great camera for outdoor security. The features on the app have been updated and work better than the Ring Doorbell.
The camera has a great live picture, and the sound is very clear.
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Reviewed in the United States on April 23, 2026