Posted on Categories Finance, History, OpinionTags

Bitcoin’s status isn’t as simple as ruling if it is more a private token or a public ledger

There is a lot of current interest in various “crypto currencies” such as Bitcoin, but that does not mean there have not been previous combined ledger and token recording systems. Others have noticed the relevance of Crawfurd v The Royal Bank (the case where money became money), and we are going to write about this yet again.

Very roughly: a Bitcoin is a cryptographic secret that is considered to have some value. Bitcoins are individual data tokens, and duplication is prevented through a distributed shared ledger (called the blockchain). As interesting as this is, we want to point out notional value existing both in ledgers and as possessed tokens has quite a long precedent.

This helps us remember that important questions about Bitcoins (such as: are they a currency or a commodity?) will be determined by regulators, courts, and legislators. It will not be a simple inevitable consequence of some detail of implementation as this has never been the case for other forms of value (gold, coins, bank notes, stocks certificates, or bank account balances).

Value has often been recorded in combinations of ledgers and tokens, so many of these issues have been seen before (though they have never been as simple as one would hope). Historically the rules that apply to such systems are subtle, and not completely driven by whether the system primarily resides in ledgers or primarily resides portable tokens. So we shouldn’t expect determinations involving Bitcoin to be simple either.

What I would like to do with this note is point out some fun examples and end with the interesting case of Crawfurd v The Royal Bank, as brought up by “goonsack” in 2013. Continue reading Bitcoin’s status isn’t as simple as ruling if it is more a private token or a public ledger

Posted on Categories Expository Writing, History, Mathematics, TutorialsTags , , , , 5 Comments on Let’s try to motivate schemes

Let’s try to motivate schemes

Recently there has been some controversy over David Mumford’s Nature magazine invited obituary of Alexander Grothendieck being initially rejected on submission (see here and here). At issue was the attempt to explain the mathematical idea of schemes (one of Alexander Grothendieck’s most important contributions) to a non-mathematician audience. Professor Mumford is a mathematician of great stature and his explanation is better than anything I could even attempt. However, in addition to the issues he raises I don’t think he was sensitive enough to what a non-mathematician considers motivation.

I’ll take a quick stab at explaining a very tiny bit of the motivation of schemes. I not sure the kind of chain of analogies argument I am attempting would work in an obituary (or in a short length), so I certainly don’t presume to advise professor Mumford on his obituary of a great mathematician (and person). Continue reading Let’s try to motivate schemes

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Working an example of von Neumann and Morgenstern utility

von Neumann and Morgenstern’s “Theory of Games and Economic Behavior” is the famous basis for game theory. One of the central accomplishments is the rigorous proof that comparative “preference methods” over fairly complicated “event spaces” are no more expressive than numeric (real number valued) utilities. That is: for a very wide class of event spaces and comparison functions “>” there is a utility function u() such that:

a > b (“>” representing the arbitrary comparison or preference for the event space) if and only if u(a) > u(b) (this time “>” representing the standard order on the reals).

However, an active reading of sections 1 through 3 and even the 2nd edition’s axiomatic appendix shows that the concept of “events” (what preferences and utilities are defined over) is deliberately left undefined. There is math and objects and spaces, but not all of them are explicitly defined in term of known structures (are they points in R^n, sets, multi-sets, sums over sets or what?). The word “event” is used early in the book and not in the index. Axiomatic treatments often rely on intentionally leaving ground-concepts undefined, but we are going to work a concrete example through von Neumann and Morgenstern to try and illustrate a bit more of the required intuition and deep nature of their formal notions of events and utility. I also will illustrate how, at least in discussion, von Neuman and Morgenstern may have held on to a naive “single outcome” intuition of events and a naive “direct dollars” intuition of utility despite erecting a theory carefully designed to support much more structure. This is possible because they never have to calculate in the general event space: they prove access to the preference allows them to construct the utility funciton u() and then work over the real numbers. Sections 1 through 3 are designed to eliminate the need for a theory of preference or utility and allow von Neuman and Morgenstern to work with real numbers (while achieving full generality). They never need to make the translations explicit, because soon after showing the translations are possible they assume they have already been applied. Continue reading Working an example of von Neumann and Morgenstern utility

Posted on Categories Computer Science, Expository Writing, History, Opinion, StatisticsTags , , 7 Comments on A Personal Perspective on Machine Learning

A Personal Perspective on Machine Learning

Having a bit of history as both a user of machine learning and a researcher in the field I feel I have developed a useful perspective on the various trends, flavors and nuances in machine learning and artificial intelligence. I thought I would take a moment to outline a bit of it here and demonstrate how what we call artificial intelligence is becoming more statistical in nature. Continue reading A Personal Perspective on Machine Learning

Posted on Categories History, StatisticsTags , , , , , ,

Deming, Wald and Boyd: cutting through the fog of analytics

This article is a quick appreciation of some of the statistical, analytic and philosphic techniques of Deming, Wald and Boyd. Many of these techniques have become pillars of modern industry through the sciences of statistics and operations research.
Continue reading Deming, Wald and Boyd: cutting through the fog of analytics

Posted on Categories Computer Science, HistoryTags ,

Hello World: An Instance Of Rhetoric in Computer Science

Hello World: An Instance Of Rhetoric in Computer Science
John Mount:

February 19, 2008

Computer scientists have usually dodged questions of intent, purpose or meaning. While there are theories that assign deep mathematical meaning to computer programs[13] we computer scientists usually avoid discussion of meaning and talk more about utility and benefit. Discussions of the rhetorical meaning of programs is even less common. However, there is a famous computer program that has a clean an important rhetorical point. This program is called “hello world” and its entire action is to write out the phrase “hello world.” The action is simple but the “hello world” program actually has a fairly significant purpose and meaning.

I would like to briefly trace the known history of “hello world” and show how the rhetorical message it presents differs from the rhetoric embodied in earlier programs. In this sense we can trace a change in the message computer scientists felt they needed to communicate (most likely due to changes in the outside world).

Continue reading Hello World: An Instance Of Rhetoric in Computer Science