Search found 8 matches

by tehtmi
Tue Mar 08, 2016 7:22 am UTC
Forum: Individual XKCD Comic Threads
Topic: 1652 "Conditionals"
Replies: 77
Views: 11760

Re: 1652 "Conditionals"

That's not being a pedant, that's being context blind. Natural language is not first-order logic. I completely agree. Presumptively, I call this the Mathematician's Fallacy (as if there was only one :)). This does seem to be something real mathematicians wrestle with -- see for example the controve...
by tehtmi
Fri Jun 18, 2010 8:23 pm UTC
Forum: Coding
Topic: Manufactoria - Make Turing Machines with Conveyor Belts
Replies: 350
Views: 94848

Re: Manufactoria - Make Turing Machines with Conveyor Belts

I'll attempt to explain Robo-children!: First, realize that swapping reds with blues (as happens a whole bunch) does not change whether or not the condition is true. The first thing that happens is a color swapping. This swapping serves no real purpose, but allows for a more efficient layout...
by tehtmi
Fri Jun 18, 2010 8:42 am UTC
Forum: Coding
Topic: Manufactoria - Make Turing Machines with Conveyor Belts
Replies: 350
Views: 94848

Re: Manufactoria - Make Turing Machines with Conveyor Belts

Smaller solutions for Robo-children! (17 parts) ?lvl=18&code=c12:7f3;b11:3f3;p11:4f2;r11:5f1;c11:6f1;q12:4f0;g12:5f3;p12:6f3;c13:4f0;c13:5f1;p13:6f6;b13:7f1;g12:3f3;c12:8f3;c12:9f3;c12:10f3;c12:11f3; Seraphim (19 parts) ?lvl=29&code=b10:5f3;p10:6f2;r10:7f1;p12:6f3;c12:9f3;c12:10f3;c12:11f3;r...
by tehtmi
Sat May 09, 2009 2:48 am UTC
Forum: Mathematics
Topic: Computer Random Number Generator - How?
Replies: 23
Views: 1906

Re: Computer Random Number Generator - How?

My impression is that randomness/pseudo-randomness performs well only when the source is independent of the application. For example, using time to seed a pseudo-random number generator is usually fine, but suppose you run your program once every hour. Then the pattern of seeds is predictable and th...
by tehtmi
Wed Apr 29, 2009 12:53 am UTC
Forum: Mathematics
Topic: Simulate dice rolls
Replies: 9
Views: 1449

Re: Simulate dice rolls

For the method of adding three uniform random variables (mentioned by the OP), here is an illustration of how good of an approximation to the normal you get: http://www.johndcook.com/blog/2009/02/12/sums-of-uniform-random-values/ If all you are worried about is minimizing the number of calls to your...
by tehtmi
Sun Jan 04, 2009 2:26 am UTC
Forum: Mathematics
Topic: Boy or Girl Paradox
Replies: 126
Views: 12312

Re: Boy or Girl Paradox

This point of view distorts the probabilities. After you ignore the cases where the child "chosen" is male, a family with two girls is twice as likely to be "reported" as a family with one girl because a parent has twice the likelihood of "choosing" a female. In effect...
by tehtmi
Sun Jan 04, 2009 1:43 am UTC
Forum: Mathematics
Topic: Boy or Girl Paradox
Replies: 126
Views: 12312

Re: Boy or Girl Paradox

What I had in mind was something like this. The parent has two children, and you are told the gender of one of the children. Given only this information, I would say its plausible that the child whose gender you were told was chosen randomly, and that being told the gender of the younger child was e...
by tehtmi
Sun Jan 04, 2009 1:08 am UTC
Forum: Mathematics
Topic: Boy or Girl Paradox
Replies: 126
Views: 12312

Re: Boy or Girl Paradox

Why should we assume that girl/girl, boy/girl, girl/boy, and boy/boy are all equally likely? This is true given a random family, but given the fact that the family has at least one girl changes this. Certainly the probability of boy/boy becomes zero, but it seems plausible to me that the probability...

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