Category Archives: software

Rich Hickey, 2

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Like Clojure, Datomic incorporates an explicit model of time. All data is associated with a time and new data does not replace old data, but is added to it. Returning to our previous example, if John later changes his address, a new datom would be added to the database, e.g.

  John, :street, “17 Maple St.”, T43

This mirrors the real world where the fact that John has moved does not erase the fact that John once lived on Swift St. This has multiple benefits: the ability to view the database at a point in time other than the present; no data is lost; the immutability of each datom allows for easy and pervasive caching.

— rjn945 15 days ago

— Hacker News

2012.03.21 Wednesday ACHK

Douglas Hofstadter, 2

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Solomon: Your entry in Wikipedia says that your work has inspired many students to begin careers in computing and artificial intelligence.

Hofstadter: I have no interest in computers. The entry is filled with inaccuracies, and it kind of depresses me.

Solomon: So fix it.

Hofstadter: The next day someone will fix it back.

— Quoted in Deborah Solomon, “The Mind Reader,” New York Times, (2007-04-01)

2012.03.16 Friday ACHK

Category Theory for Dummies

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It seems that category theory is the new hype — almost nobody actually understands what it is about, or, more importantly, what it is for. Let me tell you what it is for — it’s an important technical tool in mathematical research, which gives you new, coherent language, sometimes provides you with an additional insight in the structure of the stuff you are researching and makes it easier to notice and classify similarities between different kind of structures. Unfortunately, it is almost completely useless and uninteresting by itself — because, well, what’s interesting in objects and arrows anyway?

What make category theory interesting are its connections with various field[s] and [in] math and computer science. That’s why introducing “category theory for dummies” makes completely no sense — it’s like following Erlangen program to teach kids about points, lines and circles on a plane. The need and the significance of Erlangen program arise when you learn about many different geometries, notice what they have in common and what they do not, and try to find out what the geometry is all about. Without it, the Erlangen program is all about abstract bullshit, and the situation is completely the same with category theory. But nobody writes or posts Erlangen program for dummies on HN. Why? “General theory of everything” hype, that’s why. Erlangen program is “general theory of geometry”, but geometry seems a bit pale when compared to everything.

If you really want to understand the significance of category theory, then learn set theory, then algebra, then topology, then algebraic topology and algebraic geometry, or take abstract programming languages theory path. If you don’t care about all this stuff, because you’re hyped on the category theory, then you’re missing the point — it’s like you wanted to learn about algebraic topology, but did not care about algebra or topology.

Also anything that has “for dummies” in title should invariably remind you of Norvig’s essay (google Peter Norvig 21 days).

— xyzzyz 171 days ago

— Hacker News

2012.03.14 Wednesday ACHK

Douglas Hofstadter

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Douglas Richard Hofstadter (born February 15, 1945) is an American academic whose research focuses on consciousness, analogy-making, artistic creation, literary translation, and discovery in mathematics and physics. He is best known for his book Godel, Escher, Bach: an Eternal Golden Braid, first published in 1979, for which he was awarded the Pulitzer Prize for general non-fiction and the National Book Award for Science.

Hofstadter has said that he feels “uncomfortable with the nerd culture that centers on computers”. He admits that “a large fraction [of his audience] seems to be those who are fascinated by technology”, but when it was suggested that his work “has inspired many students to begin careers in computing and artificial intelligence” he replied that he was pleased about that, but that he himself has “no interest in computers.”

— Wikipedia on Douglas Hofstadter

2012.03.10 Saturday ACHK

Bitcoin 2

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That being said, there is a mechanism in place to combat the obvious consequences. Extreme deflation would render most currencies highly impractical: if a single Canadian dollar could suddenly buy the holder a car, how would one go about buying bread or candy? Even pennies would fetch more than a person could carry. Bitcoin, however, offers a simple and stylish solution: infinite divisibility. Bitcoins can be divided up and trade into as small of pieces as one wants, so no matter how valuable Bitcoins become, one can trade them in practical quantities.

In fact, infinite divisibility should allow Bitcoins to function in cases of extreme wallet loss. Even if, in the far future, so many people have lost their wallets that only a single Bitcoin, or a fraction of one, remains, Bitcoin should continue to function just fine. No one can claim to be sure what is going to happen, but deflation may prove to present a smaller threat than many expect.

— Won’t loss of wallets and the finite amount of Bitcoins create excessive deflation, destroying Bitcoin?

— Bitcoin Wiki on FAQ

2012.03.09 Friday ACHK

Bitcoin

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Money Supply

While the number of bitcoins in existence will never exceed 21 million, the money supply of bitcoins can exceed 21 million due to Fractional-reserve Banking.

Deflation

Because the monetary base of Bitcoins cannot be expanded, the currency would be subject to severe deflation if it becomes widely used. Keynesian economists argue that deflation is bad for an economy because it incentivises individuals and businesses to save money rather than invest in businesses and create jobs.

The Austrian school of thought counters this criticism, claiming that as deflation occurs in all stages of production, entrepreneurs who invest benefit from it. As a result, profit ratios tend to stay the same and only their magnitudes change.

In other words, in a deflationary environment, goods and services decrease in price, but at the same time the cost for the production of these goods and services tend to decrease proportionally, effectively not affecting profits. Price deflation encourages an increase in hoarding – hence savings – which in turn tends to lower interest rates and increase the incentive for entrepreneurs to invest in projects of longer term.

— Bitcoin Wiki on Controlled Currency Supply

2012.03.07 Wednesday ACHK

Time horizon

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Bezos: It does fit into my view. Our first shareholder letter, in 1997, was entitled, “It’s all about the long term.” If everything you do needs to work on a three-year time horizon, then you’re competing against a lot of people. But if you’re willing to invest on a seven-year time horizon, you’re now competing against a fraction of those people, because very few companies are willing to do that. Just by lengthening the time horizon, you can engage in endeavors that you could never otherwise pursue. At Amazon we like things to work in five to seven years. We’re willing to plant seeds, let them grow—and we’re very stubborn. We say we’re stubborn on vision and flexible on details.

In some cases, things are inevitable. The hard part is that you don’t know how long it might take, but you know it will happen if you’re patient enough. Ebooks had to happen. Infrastructure web services had to happen. So you can do these things with conviction if you are long-term-oriented and patient.

— Jeff Bezos Owns the Web in More Ways Than You Think

— By Steven Levy
   
— Wired December 2011

2012.03.06 Tuesday ACHK

Brain

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If the human brain were so simple that we could understand it, we would be so simple that we couldn’t.

— Emerson M. Pugh

— As quoted in The Biological Origin of Human Values

2012.03.03 Saturday ACHK

Meta-company

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Meta 2

“You know what’s great about the YC network? It gives the benefit of being part of a large company without being part of a big company,” Graham says. “The problem with doing a startup–even though it’s better in almost every other respect–is that you don’t have the resources of a big company to draw on. It’s very lonely; you have no one to give you advice or help you out. In a big company, you might be horribly constrained, but there are like 1,000 other people you can go to to deal with any number of problems. Now [with YC] you have 1,000 people you can go to to deal with problems, and you don’t have all the restrictions of a big company.”

— Paul Graham: Why Y Combinator Replaces The Traditional Corporation

— Austin Carr

2012.02.29 Wednesday ACHK

Lisp macros 2.2

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I think one of the problems with Lisp is that it is too powerful. It has so much meta ability that it allows people to invent their own little worlds, and it takes a while to figure out each person’s little world (SoftwareGivesUsGodLikePowers).

— Lisp is Too Powerful

2012.02.19 Sunday ACHK

Hacker News

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Hacker News is a social news website about computer hacking and startup companies, run by Paul Graham’s funding firm Y Combinator. It is different from other social news websites in that there is no option to down vote submissions; submissions can either be voted up or not voted on at all. In contrast, comments can be down voted when a user accumulates sufficient “karma,” or points gained when submissions or comments are voted up. In general, content that can be submitted is defined as “anything that gratifies one’s intellectual curiosity”.

History

The site was created by Paul Graham in February 2007. Initially it was called Startup News or occasionally News.YC. On August 14, 2007 it became known by its current name. It developed as a project of his company Y Combinator, functioning as a real-world application of the Arc programming language which Graham co-developed.

The intention was to recreate a community similar to the early days of Reddit. Graham has stated he hopes to avoid the Eternal September that results in the general decline of intelligent discourse within a community.

— Wikipedia on Hacker News

2012.02.17 Friday ACHK

Life hacking 4

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The term life hack refers to productivity tricks that computer programmers devise and employ to cut through information overload and organize their data. In more recent times, the same phrase has expanded to any sort of trick, shortcut, skill, or novelty method to increase productivity and efficiency, in all walks of life; in other words, anything that solves an everyday problem in a clever or non-obvious way might be called a life hack.

The original definition of the term hack is an inelegant but effective solution to a specific computing problem.

— Wikipedia on Life hack

2012.02.16 Thursday ACHK

Exploding Offer Season

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2. If you get an exploding offer from a company that’s not your first choice, push back. Say, “I’m sorry, I’m not going to be able to give you an answer until January 14th. I hope that’s OK.” Almost any company, when pressed, will give you a chance to compare offers. Don’t worry about burning bridges or pissing anyone off. Trust me on this one: there’s not a single hiring manager in the world who wants to hire you but would get mad just because you’re considering other offers. It actually works the other way. When they realize you’re in demand, they’ll want you more.

— Joel Spolsky

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2012.02.15 Wednesday ACHK

Not average

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Those in the print media who dismiss the writing online because of its low average quality are missing an important point: no one reads the average blog. In the old world of channels, it meant something to talk about average quality, because that’s what you were getting whether you liked it or not. But now you can read any writer you want. So the average quality of writing online isn’t what the print media are competing against. They’re competing against the best writing online. And, like Microsoft, they’re losing.

— What Business Can Learn from Open Source

— Paul Graham

2012.02.12 Sunday ACHK

Curry–Howard correspondence, 3

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Haskell is a standardized, general-purpose purely functional programming language, with non-strict semantics and strong static typing. It is named after logician Haskell Curry. In Haskell, “a function is a first-class citizen” of the programming language. As a functional programming language, the primary control construct is the function. The language is rooted in the observations of Haskell Curry and his intellectual descendants, that “a proof is a program; the formula it proves is a type for the program“.

— Wikipedia on Haskell (programming language)

2012.02.07 Tuesday ACHK

Exponential delay

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We also have some new features to prevent flamewars. The most conspicuous is an exponential delay before reply links appear on deeply nested comments. We’d noticed these were rarely the most interesting comments on the site. We’re hoping that instead of killing stupid arguments, it will be sufficient to apply gradually increasing drag to them.

— 29 Apr 2009: Faster, Fewer Flamewars

— Paul Graham

2012.02.03 Friday ACHK

Hyperthymesia

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Hyperthymesia, also known as piking or hyperthymestic syndrome is a condition in which the individual possesses a superior autobiographical memory, meaning they can recall the vast majority of personal experiences and events in their lives.

Defining characteristics

Individuals with hyperthymesia can recall almost every day of their lives in near perfect detail, as well as public events that hold some personal significance to them. Those affected describe their memories as uncontrollable associations, when they encounter a date, they “see” a vivid depiction of that day in their heads. Recollection occurs without hesitation or conscious effort.

It is important to draw a distinction between those with hyperthymesia and those with other forms of exceptional memory, who generally use mnemonic or similar rehearsal strategies to memorise long strings of subjective information.

— Wikipedia on Hyperthymesia

2012.02.02 Thursday ACHK