Re:Pi in the Sky, Artists Fill the SF Bay Area With w/ first...
by archgoon on Thursday September 13, 2012 @06:24PM
(#4518963)
I hate tau. An event like this should be viewed as a cool nerdy thing, a celebration of the culture and fun of mathematics. Thanks to tau, nerds start bickering over a senseless and useless distinction as to whether a factor of two should be present in a transcendental constant. Did we really need another pointless division and source of argument in our society?
Re:Pi in the Sky, Artists Fill the SF Bay Area With w/ first...
by gms7777 on Thursday September 13, 2012 @02:17PM
(#4517705)
They really should have done this for Pi day. I may have missed it in the article, was there anything significant about their choosing yesterday for this event?
Re:Pi in the Sky, Artists Fill the SF Bay Area With w/ first...
by philh on Thursday September 13, 2012 @01:39PM
(#4517518)
μ
--
To clarify, that's not a thing you can meaningfully do. It makes sense to define your units such that, e.g. c=1, because c has units (distance per time). You're really adjusting your units, not your numbers. But π is dimensionless. Diameter and circumference are both measures of distance, and they are never equal.
If you say "this number times one equals that number", and the numbers aren't the same, then when you say "one" you don't actually mean "one" the way anyone else speaks about it. (By convention: whenever you can do multiplication, if there's something called "one", then "one" is the multiplicative identity.)
There's nothing to stop you from, e.g. renaming all numbers x -> x/π. But you wouldn't gain anything; you'd just say things like "1/π squared is 1/π", and "1 squared is π", and "π times 1/π is π". It looks weird, but what's happening is perfictly ordinary, just with weird names.
Re:Pi in the Sky, Artists Fill the SF Bay Area With w/ first...
by anonymouz on Thursday September 13, 2012 @02:47PM
(#4517870)
One could sort of satisfy naturalethic's wish by choosing a numeral system with pi as basis. Then pi would have digit representation '1' in this system. And yes, mathematicians have studied transcendental bases for numeral systems (Knuth in particular, see the short paragraph on http://mathworld.wolfram.com/Base.html which explicitly mentions pi as basis).
Of course it's not a good idea to base your day-to-day numeral system on pi, but I know that at least for irrational bases there are actual applications.
Re:Pi in the Sky, Artists Fill the SF Bay Area With w/ first...
by mej10 on Thursday September 13, 2012 @03:01PM
(#4517953)
This is a good point as well, and more in line with what the original commenter was asking.
Using pi as a base is even briefly discussed on wikipedia. I had some interest in using e as the basis for a while, since (as is pointed out on wiki) "The base e is the most economical choice of radix β > 1 (Hayes 2001), where the radix economy is measured as the product of the radix and the length of the string of symbols needed to express a given range of values."
Re:Pi in the Sky, Artists Fill the SF Bay Area With w/ first...
by jerf on Thursday September 13, 2012 @03:48PM
(#4518183)
"One could sort of satisfy naturalethic's wish by choosing a numeral system with pi as basis. Then pi would have digit representation '1' in this system."
I'm pretty sure pi comes out to 10 base pi, not 1 base pi.
Re:Pi in the Sky, Artists Fill the SF Bay Area With w/ first...
by jerf on Friday September 14, 2012 @10:20PM
(#4525007)
I'd refer you back to philh's answer. You can do that and it isn't "wrong", but it is surprisingly uninteresting, as compared to a discussion of irrational or negative or imaginary bases.
Re:Pi in the Sky, Artists Fill the SF Bay Area With w/ first...
by anonymouz on Thursday September 13, 2012 @03:43PM
(#4518148)
Careful, none of these actually "set pi=1".
Also, since pi is transcendental, the field would not be an algebraic number field, but in fact isomorphic to the rational functions over Q, i.e., quotients of polynomials with coefficients in Q.
--
To clarify, that's not a thing you can meaningfully do. It makes sense to define your units such that, e.g. c=1, because c has units (distance per time). You're really adjusting your units, not your numbers. But π is dimensionless. Diameter and circumference are both measures of distance, and they are never equal.
If you say "this number times one equals that number", and the numbers aren't the same, then when you say "one" you don't actually mean "one" the way anyone else speaks about it. (By convention: whenever you can do multiplication, if there's something called "one", then "one" is the multiplicative identity.)
There's nothing to stop you from, e.g. renaming all numbers x -> x/π. But you wouldn't gain anything; you'd just say things like "1/π squared is 1/π", and "1 squared is π", and "π times 1/π is π". It looks weird, but what's happening is perfictly ordinary, just with weird names.
Of course it's not a good idea to base your day-to-day numeral system on pi, but I know that at least for irrational bases there are actual applications.
Using pi as a base is even briefly discussed on wikipedia. I had some interest in using e as the basis for a while, since (as is pointed out on wiki) "The base e is the most economical choice of radix β > 1 (Hayes 2001), where the radix economy is measured as the product of the radix and the length of the string of symbols needed to express a given range of values."
http://en.wikipedia.org/wiki/Non-integer_representation#Exam...
I'm pretty sure pi comes out to 10 base pi, not 1 base pi.
"a numeral system with pi as basis" could be (base pi)pi, where pi =-> '1' and pipi -> '10' and unity -> '0.1'.
You can subtract (pi - 1) from every number, giving you a translation of the real numbers.
You can divide everything by pi, giving you a slight compression that ultimately doesn't mean anything.
You could use it to create a field extension of the rationals, giving you a http://en.wikipedia.org/wiki/Algebraic_number_field where {1, pi} is the basis.
But to answer your question: probably nothing.
Also, since pi is transcendental, the field would not be an algebraic number field, but in fact isomorphic to the rational functions over Q, i.e., quotients of polynomials with coefficients in Q.
I think my head just exploded.