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The Greek mathematician Euclid may very well have proved, circa 300 BCE, that there are infinitely many prime numbers. But it was the British mathematician Christian Lawson-Perfect who, more recently, devised the computer game “Is this prime?”

Launched five years ago, the game surpassed three million tries on July 16—or, more to the point, it hit run 2,999,999—after a Hacker News post generated a surge of about 100,000 attempts.

The aim of the game is to sort as many numbers as possible into “prime” or “not prime” in 60 seconds (as Lawson-Perfect originally described it on The Aperiodical, a mathematics blog of which he’s a founder and editor).

A prime number is a whole number with precisely two divisors, 1 and itself.

“It’s very simple, but infuriatingly difficult,” says Lawson-Perfect, who works in the e-learning unit in Newcastle University’s School of Mathematics and Statistics. He created the game in his spare time, but it’s proved useful on the job: Lawson-Perfect writes e-assessment software (systems that evaluate learning). “The system I make is designed to randomly generate a maths question, and take an answer from the student, which it automatically marks and gives feedback on,” he says. “You could view the primes game as a kind of assessment”—he’s used it when doing outreach sessions in schools.

He made the game slightly easier with keyboard shortcuts—the y and n keys click the corresponding yes-no buttons on the screen—in order to save mouse-moving time.

Give it a whirl:

Primality-checking algorithms

Prime numbers have practical utility in computing—such as with error-correcting codes and encryption. But while prime factorization is hard (hence its value in encryption), primality checking is easier, if tricky. The Fields Medal–winning German mathematician Alexander Grothendieck infamously mistook 57 for prime (the “Grothendieck prime”). When Lawson-Perfect analyzed data from the game, he found that various numbers exhibited a certain “Grothendieckyness.” The number most often mistaken for a prime was 51, followed by 57, 87, 91, 119, and 133—Lawson-Perfect’s nemesis (he also devised a handy primality-checking service: https://isthisprime.com/2).

The most minimalistic algorithm for checking a number’s primeness is trial division—divide the number by every number up to its square root (the product of two numbers greater than the square root would be greater than the number in question).

However, this naïve method is not very efficient, and neither are some other techniques devised over the centuries—as the German mathematician Carl Friedrich Gauss observed in 1801, they “require intolerable labor even for the most indefatigable calculator.”

The algorithm Lawson-Perfect coded up for the game is called the Miller-Rabin primality test (which builds on a very efficient but not ironclad 17th-century method, “Fermat’s little theorem”). The Miller-Rabin test works surprisingly well. As far as Lawson-Perfect is concerned, it’s “basically magic”—“I don’t really understand how it works, but I’m confident I could if I spent the time to look at it more deeply,” he says.

Since the test uses randomness, it produces a probabilistic result. Which means that sometimes the test lies. “There is a chance of uncovering an imposter, a composite number that is trying to pass as prime,” says Carl Pomerance, a mathematician at Dartmouth College and coauthor of the book Prime Numbers: A Computational Perspective. The chances of an imposter slipping through the algorithm’s clever checking mechanism are maybe one in a trillion, though, so the test is “pretty safe.”

But as far as clever primality checking algorithms go, the Miller-Rabin test is “the tip of the iceberg,” says Pomerance. Notably, 19 years ago, three computer scientists—Manindra Agrawal, Neeraj Kayal, and Nitin Saxena, all at the Indian Institute of Technology Kanpur—announced the AKS primality test (again building upon Fermat’s method), which finally provided a test for unequivocally proving that a number is prime, with no randomization and (theoretically, at least) with impressive speed. Alas, fast in theory doesn’t always translate to fast in real life, so the AKS test isn’t useful for practical purposes.

The unofficial world record

But practicality isn’t always the point. Occasionally Lawson-Perfect receives email from people keen to share their high scores in the game. Recently a player reported 60 primes in 60 seconds, but the record is more likely 127. (Lawson-Perfect doesn’t track high scores; he knows there are some cheaters, with computer-aided attempts that produce spikes in the data.)

The 127 score was achieved by Ravi Fernando, a mathematics graduate student at the University of California, Berkeley, who posted the result in July 2020. It’s still his personal best and, he

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By: Siobhan Roberts
Title: Is 57 a prime number? There’s a game for that.
Sourced From: www.technologyreview.com/2021/07/18/1029440/prime-number-game/
Published Date: Sun, 18 Jul 2021 10:00:00 +0000

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LATAM crypto exchange Bitso and FMF launch NFT of Mexico’s National Team jerseys

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Bitso, a leading cryptocurrency platform operating in Latin America, and the Mexican Football Federation (FMF), today announced the joint launch of the first collectible NFT of the Mexico National Team’s jerseys that was acquired in cryptocurrencies.

This morning through their social media platforms, the FMF and Bitso announced the opportunity to acquire the new official National Team fan jerseys ahead of the team’s participation in the 2022 World Cup. In just 20 minutes, the entire collection sold out.

bitsonftjeysey
The NFTs of the jerseys have an exclusive design for the metaverse – each is unique on the blockchain and can be resold by its owner in subsequent transactions.

The collection consisted of 100 official physical jerseys, each with a corresponding NFT version of the jersey that fans’ avatars can wear within the Decentraland metaverse. Each physical and NFT jersey set sold for the equivalent of $1,800 MXN in ethers.

“Our mission is to make cryptocurrency useful in the everyday life of Mexicans; we are committed to spreading the technology through innovative opportunities that help people throughout the country familiarize themselves with this new world. We are very excited to offer the incredible, historic opportunity for the fans of our National Team so that through their Bitso account, they can wear the colors of the National Team on and ‘off’ the field in the metaverse.”
– Bárbara González Briseño, General Director of Bitso México

Jersey NFTs

Created by Bitso, the virtual jersey sports the official colors of Mexico and the new National Team shield, characteristics that will make it stand out when users wear it in the virtual world of Decentraland.

The post LATAM crypto exchange Bitso and FMF launch NFT of Mexico’s National Team jerseys appeared first on CryptoNinjas.

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By: CryptoNinjas.net
Title: LATAM crypto exchange Bitso and FMF launch NFT of Mexico’s National Team jerseys
Sourced From: www.cryptoninjas.net/2022/07/29/latam-crypto-exchange-bitso-and-fmf-launch-nft-of-mexicos-national-team-jerseys/
Published Date: Fri, 29 Jul 2022 15:19:02 +0000

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Long-running crypto exchange EXMO unveils “lively” rebrand amidst growth

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EXMO, a crypto exchange platform operating since 2014, announced this week a rebranded visual identity with includes a new logo, brand colors, and design features. This new branding comes as EXMO continues to grow its crypto platform while also seeking to expand its presence in other jurisdictions.

Some new developments underway at EXMO:

Soon, users will be able to earn passive income from EXMO’s new staking platform.Plans to launch an EXMO crypto debit card.Expansion of its services in international markets with the opening of offices in Poland and Lithuania.

EXMO’s new logo

The rationale for the re-brand:

“At EXMO, we have a vision of a world where crypto is in every wallet. Hassle-free. We want to achieve this by making crypto as simple and accessible to everyone as possible. And we know that you already appreciate EXMO for offering user-friendly services and helpful support. Also for the opportunity to trade anywhere and anytime, closing deals in just a few taps. Such important changes required a rethinking of our corporate style, which has long needed a massive upgrade. So today we are introducing a new brand identity for EXMO with a completely new visual concept. We are launching a new logo, brand colors, and design elements. Our key design principles are simplicity, boldness, and a pinch of fun. But most importantly, we have changed our logo. Simple and easily recognizable, it represents the humanity of our brand. The logo stands out due to the wavy letter ‘m’ which symbolizes exchange rate charts and also resembles a spring that will launch you into the crypto world.”
– The EXMO Team regarding the re-branding

The post Long-running crypto exchange EXMO unveils “lively” rebrand amidst growth appeared first on CryptoNinjas.

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By: CryptoNinjas.net
Title: Long-running crypto exchange EXMO unveils “lively” rebrand amidst growth
Sourced From: www.cryptoninjas.net/2022/07/26/long-running-crypto-exchange-exmo-unveils-lively-rebrand-amidst-growth/
Published Date: Tue, 26 Jul 2022 08:10:38 +0000

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Stitching together the grid will save lives as extreme weather worsens

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The blistering heat waves that set temperature records across much of the US in recent days have strained electricity systems, threatening to knock out power in vulnerable regions of the country. 

The electricity has largely stayed online so far this summer, but there have been scattered problems and close calls already. 

Heavy use of energy-sucking air-conditioners is the biggest problem. But intense heat can also reduce the output of power plants, blow transformers, and force power lines to sag. Severe droughts across large parts of the country have also significantly reduced the availability of hydroelectric power, according to the North American Electric Reliability Corporation (NERC). 

It’s unlikely to get better soon. A number of grid operators may struggle to meet peak summer demand, creating the risk of rolling blackouts, the NERC report notes.

The nation’s isolated and antiquated grids are in desperate need of upgrades to keep the lights, heat, and air-conditioning on in the midst of extreme weather events that climate change is making more common, severe, and dangerous. One clear way to ease many of these issues is to more tightly integrate the country’s regional grids, stitching them together with more long-range transmission lines. 

If electricity generated in one area can be more easily shared across much wider regions, power can simply flow to where it’s needed at those moments when customers crank up air-conditioners en masse, or when power plants or fuel supply lines fail amid soaring temperatures, wildfires, hurricanes, or other events, says Liza Reed, a research manager focused on transmission at the Niskanen Center, a Washington, DC, think tank.  

The problem is it’s proved difficult to build more long-range transmission and grid interconnections for a variety of reasons, including the permitting challenges of erecting wires through private and public lands across cities, counties, and states and the reluctance of local authorities to forfeit control or submit to greater federal oversight.

The case of Texas

The unreliability of the US grid is not a new problem. Severe heat and winter storms have repeatedly exposed the frailty of electricity systems in recent years, leaving thousands to millions of people without power as temperatures spiked or plunged.

One of the fundamental challenges is that the grids today are highly fragmented. There are three main electricity networks within the US: the Eastern Grid, the Western Grid, and the Electric Reliability Council of Texas (ERCOT). But there are numerous regional transmission organizations within those first two systems, including the California Independent System Operator, Southwest Power Pool, PJM Interconnection, New York ISO, and more. 

These grids form a complex web of networks operating under different regulators, rules and market structures, and often with limited connections between them.

Map USA grid
A variety of regional transmission organizations oversee different parts of the nation’s aging and fragmented grids, which operate under different rules and with often limited connections between them.
legend

ERCOT is especially isolated, in part because of the desire among local politicians, citizens, and power companies to avoid added competition, the hassle of following other states’ rules, and oversight from the Federal Energy Regulatory Commission (FERC). But the state offers a case study in why that can be a serious problem amid increasingly harsh climate conditions, Reed says.

The Texas grid operator pleaded with customers several times earlier this month to cut electricity use as blistering summer temperatures created  demand surges that threatened to outstrip supply and require rolling blackouts.  Low wind conditions, cloud cover, and outages at fossil-fuel power plants added to the strains.

Shutting off the electricity needed to run air-conditioning in triple-digit temperatures

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By: James Temple
Title: Stitching together the grid will save lives as extreme weather worsens
Sourced From: www.technologyreview.com/2022/07/28/1056483/stitching-together-the-grid-will-save-lives-as-extreme-weather-worsens/
Published Date: Thu, 28 Jul 2022 08:00:00 +0000

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