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Problem: Prove there are infinitely many primes Solution: Denote by $ \pi(n)$ the number of primes less than or equal to $ n$. We will give a lower bound on $ \pi(n)$ which increases without bound as $ n \to \infty$. Note that every number $ n$ can be factored as the product of a square free number $ r$ (a number which no square divides) and a square $ s^2$.
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Problem: Prove there are infinitely many primes Solution: Denote by $ \pi(n)$ the number of primes less than or equal to $ n$. We will give a lower bound on $ \pi(n)$ which increases without bound as $ n \to \infty$. Note that every number $ n$ can be factored as the product of a square free number $ r$ (a number which no square divides) and a square $ s^2$.
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Problem: Prove there are infinitely many primes Solution: Denote by $ \pi(n)$ the number of primes less than or equal to $ n$. We will give a lower bound on $ \pi(n)$ which increases without bound as $ n \to \infty$. Note that every number $ n$ can be factored as the product of a square free number $ r$ (a number which no square divides) and a square $ s^2$.
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Last night I had the opportunity to hear Jason Fried, founder of 37signals, voice his thoughts on entrepreneurship.
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Today, the first official Tea Club meeting took place. It was attended by Dave, Phil and Sam. It was held from approximately 3pm until 7pm, and a wide variety of topics were discussed.
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Today, the first official Tea Club meeting took place. It was attended by Dave, Phil and Sam. It was held from approximately 3pm until 7pm, and a wide variety of topics were discussed.
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I am writing a keepalived module for puppet. It will naturally be called: “puppet-keepalived”, and I will be releasing the code in the near future! In any case, if you’re familiar with VRRP , you’ll know that each managed link (eg: resource or VIP ) has a common routerid and password which are shared among all members in the group. It is important that these parameters are unique across the type definitions on a single node.
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I am writing a keepalived module for puppet. It will naturally be called: “puppet-keepalived”, and I will be releasing the code in the near future! In any case, if you’re familiar with VRRP , you’ll know that each managed link (eg: resource or VIP ) has a common routerid and password which are shared among all members in the group. It is important that these parameters are unique across the type definitions on a single node.
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Given the following code Map
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A few weeks back I did a brief feature highlight on Postgres arrays . Since that time I’ve found myself using them with increasing regularity on small side projects. Much of this time I’m using Django and of course not opting to write raw SQL to be able to use arrays. Django actually makes it quite simple to work with Arrays in Postgres with a package by Andrey Antukh . Lets get started by installing two libraries: pip install djorm-ext-....
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A few weeks back I did a brief feature highlight on Postgres arrays . Since that time I’ve found myself using them with increasing regularity on small side projects. Much of this time I’m using Django and of course not opting to write raw SQL to be able to use arrays. Django actually makes it quite simple to work with Arrays in Postgres with a package by Andrey Antukh . Lets get started by installing two libraries: pip install djorm-ext-....
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In a curious turn of events, the Plone team is considering to remove their inline editing feature around the same time when similar features are being added to popular CMSs like TYPO3 and Drupal . While the reason why Ploners are considering to remove the feature is technical, wanting to remove an old library dependency, the discussion thread contains quite a lot of people complaining about inline editing. Some examples: No pro....
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In our last primer we looked at a number of interesting examples of metric spaces, that is, spaces in which we can compute distance in a reasonable way. Our goal for this post is to relax this assumption. That is, we want to study the geometric structure of space without the ability to define distance. That is not to say that some notion of distance necessarily exists under the surface somewhere, but rather that we include a whole new class..
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In our last primer we looked at a number of interesting examples of metric spaces, that is, spaces in which we can compute distance in a reasonable way. Our goal for this post is to relax this assumption. That is, we want to study the geometric structure of space without the ability to define distance. That is not to say that some notion of distance necessarily exists under the surface somewhere, but rather that we include a whole new class..
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In our last primer we looked at a number of interesting examples of metric spaces, that is, spaces in which we can compute distance in a reasonable way. Our goal for this post is to relax this assumption. That is, we want to study the geometric structure of space without the ability to define distance. That is not to say that some notion of distance necessarily exists under the surface somewhere, but rather that we include a whole new class..
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Intel® Architecture Instruction Set Extensions Programming Reference (PDF reference). The description of new instructions in the upcoming Haswell processor, including transactional memory support, hardware random number generator, and 256-bit vector integer operations. The transactional memory instructions should be useful for GIL (global interpreter lock) in Python and Ruby. They tried to eliminate it with software TM, but it was too slo..
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I love my keyboard shortcuts, and I sometimes I want to change them. If you’re ever in a gnome application and wanted to change that one right there , you can now live-edit them! In a terminal, first enable this feature: gsettings set org.gnome.desktop.interface can-change-accels true Next, hover over the menu item shortcut that you want to change. Enter the shortcut you want. It should update immediately! I like to disable this ..
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I love my keyboard shortcuts, and I sometimes I want to change them. If you’re ever in a gnome application and wanted to change that one right there , you can now live-edit them! In a terminal, first enable this feature: gsettings set org.gnome.desktop.interface can-change-accels true Next, hover over the menu item shortcut that you want to change. Enter the shortcut you want. It should update immediately! I like to disable this ..
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The relation between Create.js and the TYPO3 team goes back a long way. They were present in the IKS event in February 2011 in Vienna where I presented Create for the first time. My original idea had been to just build a new content editing interface for Midgard , but as they also were interested, we ended up removing the Midgard dependencies and building Create and VIE as a fully CMS-agnostic interface, a key part of decoupled cont....
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The web has come a long way. We have APIs that allow developers to create amazing applications quickly, and browser technologies have…
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The web has come a long way. We have APIs that allow developers to create amazing applications quickly, and browser technologies have…
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Bought a new computer, decided to try out Ubuntu Linux . Here’s my report of things i liked, things that worked, things I disliked, and things that didn’t work. Things that are improvements over Windows and Mac: Single update manager! No more Java, Adobe, Windows etc updates. My experience with Mac (at least 10.4) wasn’t much better. The Debian/Ubuntu update manager is extensible in the sense you can add random internet addresses for....
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A question that came up at an event I was at yesterday: How will the time between the first (commercial) deployment of a telephony service, and a regulated universal service obligation for telephony compare to that of the time between the first (commercial) Internet services being deployed and a USO for IP connectivity (e.g., Broadband)? Based on this, is the cycle time of the telephony regulatory bodies, and mechanisms through which ..
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A question that came up at an event I was at yesterday: How will the time between the first (commercial) deployment of a telephony service, and a regulated universal service obligation for telephony compare to that of the time between the first (commercial) Internet services being deployed and a USO for IP connectivity (e.g., Broadband)? Based on this, is the cycle time of the telephony regulatory bodies, and mechanisms through which ..
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Gwen Shapira has written a nice summary of a problem case where the classic wait interface based troubleshooting method is not always enough for troubleshooting low-level issues. The top SQL + top wait approach should usually be used as the starting point of troubleshooting a session, workload etc, but often the troubleshooting does not stop there. So, when the wait interface and related tools don’t explain the problem well enough, then..
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Gwen Shapira has written a nice summary of a problem case where the classic wait interface based troubleshooting method is not always enough for troubleshooting low-level issues. The top SQL + top wait approach should usually be used as the starting point of troubleshooting a session, workload etc, but often the troubleshooting does not stop there. So, when the wait interface and related tools don’t explain the problem well enough, then..
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In the classic arcade game Galaga (1981), there is a well-known cheat for those who are patient. If you destroy all of the enemies on Stage 1 except for the left two enemies (shown to the right), then dodge their fire for about 10-15 minutes, they stop firing at you. At this point, you can safely kill them and no enemies will fire at you for the remainder of the game (they can still crash into you to kill you though).
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In the classic arcade game Galaga (1981), there is a well-known cheat for those who are patient. If you destroy all of the enemies on Stage 1 except for the left two enemies (shown to the right), then dodge their fire for about 10-15 minutes, they stop firing at you. At this point, you can safely kill them and no enemies will fire at you for the remainder of the game (they can still crash into you to kill you though).
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Thursday I entered in my first hackathon, Enova’s No Limit Code’em. I partnered with my friend Vaib, a fellow Starter League student.
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I present to you, "Voxel Levitation: a Step-by-Step Guide". Step 1: Step 2: Step 3: Step 4: Also, check it out. Hurricane Sandy has spilled over into Lemma. It's raining! That is all.
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The sidebar in Mutt is useful if you have multiple email accounts and want to switch between them quickly. It shows you each inbox with a number of unread emails. I have 6 Gmail accounts plugged into my Mutt and here is what I used to see. INBOX (1) INBOX INBOX (2) INBOX (1) INBOX (7) INBOX And I had to remember which one was which. Let’s say you have your mailboxes in ~/.mail. $ ls ~/.mail work home Create a directory called aliases..
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The sidebar in Mutt is useful if you have multiple email accounts and want to switch between them quickly. It shows you each inbox with a number of unread emails. I have 6 Gmail accounts plugged into my Mutt and here is what I used to see. INBOX (1) INBOX INBOX (2) INBOX (1) INBOX (7) INBOX And I had to remember which one was which. Let’s say you have your mailboxes in ~/.mail. $ ls ~/.mail work home Create a directory called aliases..
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Hello fellow readers, I've been away of the social networking scene for a year, after obvious wrong events such as Facebook entering the stock market. This post is a reminder of those horrible, so called, online social networks. Social networks make people look stupid! On a personal level, I've been out for a year and I still feel the weird nausea arising when looking at people wasting their precious time on those networks; wandering, l..
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Logos are a trap. Let me explain that statement: they are a place many startups get stuck. A logo is what identifies you. It's the symbol that takes up space in a customer's mind when they think about your company. There is no symbol that is more connected to your company than a logo. This traps entrepreneurs because it drives many of us to want the perfect logo. This is how I got Review Signal's logo created in 3 days from start to fin....
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Logos are a trap. Let me explain that statement: they are a place many startups get stuck. A logo is what identifies you. It's the symbol that takes up space in a customer's mind when they think about your company. There is no symbol that is more connected to your company than a logo. This traps entrepreneurs because it drives many of us to want the perfect logo. This is how I got Review Signal's logo created in 3 days from start to fin....
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This is a step by step guide in which I will show you how to setup WordPress with maximum speed and performance for just $15 per month utilizing Nginx + PHP-FPM + APC + Cloudflare + Redis. It is the same that this blog is using and I will show you how. No need for [...]
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This is a step by step guide in which I will show you how to setup WordPress with maximum speed and performance for just $15 per month utilizing Nginx + PHP-FPM + APC + Cloudflare + Redis. It is the same that this blog is using and I will show you how. No need for [...]
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For anyone that attended my talk “Moving from Manual to Automated Builds” at Tech Mixer U, I'm posted the slides with extra notes and our full demo ant script.
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