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### Re: Specific Question Discussion

Posted: **Sun Oct 23, 2016 3:38 pm**

by **khannate**

Could I see the tossups on primes and variance please? I'll also add that I was frustrated by the tangrams tossup as well, since they don't seem to have any importance other than being a cute puzzle, and aren't really something you would hear about while learning math.

### Re: Specific Question Discussion

Posted: **Sun Oct 23, 2016 8:01 pm**

by **otsasonr**

Silverman wrote:Inifinite Jest wrote:Boolean operators are equivalent to logical connectives

Right, but you're not simplifying the connectives themselves, you're simplifying the expression as a whole. That's like saying "conjunctions" when the question wants "sentences" (in a natural language sense).

The answer line should definitely include other answers like "logic expressions" or "logic circuits", since these are also common terms for the same thing in this context.

### Re: Specific Question Discussion

Posted: **Sun Oct 23, 2016 8:21 pm**

by **Considered Harmful**

otsasonr wrote:Silverman wrote:Inifinite Jest wrote:Boolean operators are equivalent to logical connectives

Right, but you're not simplifying the connectives themselves, you're simplifying the expression as a whole. That's like saying "conjunctions" when the question wants "sentences" (in a natural language sense).

The answer line should definitely include other answers like "logic expressions" or "logic circuits", since these are also common terms for the same thing in this context.

I agree that there were a number of missing alternate answers. I also have doubts about whether "Booleans" should be an acceptable answer. I have only ever seen "Booleans" refer to individual variables, and not entire expressions.

### Re: Specific Question Discussion

Posted: **Sun Oct 23, 2016 8:53 pm**

by **Ike**

Sorry I've been away from this for a while.

The answer line should definitely include other answers like "logic expressions" or "logic circuits", since these are also common terms for the same thing in this context.

No, you're wrong. In particular, all of these algorithms only work if the logic expressions are Boolean logic expressions. For example, you cannot simplify them using any of these methods if they are fuzzy logic expressions. Perhaps answers are promptable, but certainly not acceptable.

### Re: Specific Question Discussion

Posted: **Mon Oct 24, 2016 12:49 am**

by **otsasonr**

Ike wrote:Sorry I've been away from this for a while.

The answer line should definitely include other answers like "logic expressions" or "logic circuits", since these are also common terms for the same thing in this context.

No, you're wrong. In particular, all of these algorithms only work if the logic expressions are Boolean logic expressions. For example, you cannot simplify them using any of these methods if they are fuzzy logic expressions. Perhaps answers are promptable, but certainly not acceptable.

Oh, of course, there's definitely not a commonly used convention that unless otherwise specified, logic refers to ordinary two-valued logic. That would be ridiculous, and is definitely not something that anyone who has actually ever worked with digital logic knows.

It is certainly not so common that I was able to find a set of

course notes using that convention in 5 seconds. Or

another one (here they are referred to as logic functions). Or maybe even a textbook [1].

**References**
[1] R. F. Tinder.

*Engineering Digital Design*. San Diego, CA. Academic Press, 2000

### Re: Specific Question Discussion

Posted: **Mon Oct 24, 2016 1:11 am**

by **Ike**

otsasonr wrote:Ike wrote:Sorry I've been away from this for a while.

The answer line should definitely include other answers like "logic expressions" or "logic circuits", since these are also common terms for the same thing in this context.

No, you're wrong. In particular, all of these algorithms only work if the logic expressions are Boolean logic expressions. For example, you cannot simplify them using any of these methods if they are fuzzy logic expressions. Perhaps answers are promptable, but certainly not acceptable.

Oh, of course, there's definitely not a commonly used convention that unless otherwise specified, logic refers to ordinary two-valued logic. That would be ridiculous, and is definitely not something that anyone who has actually ever worked with digital logic knows.

It is certainly not so common that I was able to find a set of

course notes using that convention in 5 seconds. Or

another one (here they are referred to as logic functions). Or maybe even a textbook [1].

**References**
[1] R. F. Tinder.

*Engineering Digital Design*. San Diego, CA. Academic Press, 2000

Again, all of these examples are using the set of logic expressions that coincides with the set of valid Boolean functions. I think you understand that the set of all possible logical expressions is a superset of the set of all Boolean functions -- you can't accept that answer, (I've updated the prompt line to include a prompt on "logical expressions). While I'm a little sympathetic to the idea that you may be in a discipline where the shorthand means that "logic" means "two-valued logic", you must indicate in some way that this is either "0-1 logic" or "Boolean logic" since contra your posts, it is perfectly "ordinary" to use polyvalent logics.

### Re: Specific Question Discussion

Posted: **Mon Oct 24, 2016 1:33 am**

by **Amizda Calyx**

It's promptable, shouldn't be outright acceptable... Propositional logic formula or expression ought to be in the answer though. A minor nitpick: the "conjunctive normal" clue seems to be conflating boolean functions with boolean formulas, which further supports "formulas" as an answerline. Maybe EE students are actually taught that the referent of "logical expression" is what the rest of the world calls a boolean expression and they just happen to be unaware of this fact, and also unaware that other logics exist. It depends on whether you want to not penalize people for partial knowledge and how much stock you put into language-as-use -- to what extent is a word defined by the people who use it, or by how many people use it in a specific way.

¯\_(ツ)_/¯

### Re: Specific Question Discussion

Posted: **Mon Oct 24, 2016 1:33 am**

by **Emperor Pupienus**

khannate wrote:Could I see the tossups on primes and variance please? I'll also add that I was frustrated by the tangrams tossup as well, since they don't seem to have any importance other than being a cute puzzle, and aren't really something you would hear about while learning math.

EFT Packet 1 wrote:
6. The bootstrap method was devised as an improvement to the jackknife method for estimating this quantity for a sample. Bartlett’s test may be used to determine if a number of samples are from populations with equal values of this quantity, a condition known as homoscedasticity. For the geometric distribution, this quantity is equal to [read slowly] “one minus p over p squared.” If a continuous distribution lacks an (*) expected value, then it also lacks a value for this quantity; that is because this quantity is defined as the square of the expected value minus the expected value squared. This quantity, which is the second moment of a distribution, is equal to the square of the standard deviation. For 10 points, name this quantity that measures the amount of spread in a data sample.

ANSWER: variance [prompt on homoscedasticity until read]

EFT Packet 4 wrote:
14. Samuel Yates coined the term “titanic” for examples of these values that are written in the form of 10 to the power 999 plus n, with the smallest n being equal to 7. These values raised to “p minus 1 divided by 2” are congruent to the Legendre symbol of these values over p mod p according to Euler’s criterion. A topological proof about these numbers was given by Hillel Furstenberg. Eisenstein integers with this property are (*) irreducible. Perfect numbers have a one-to-one correspondence with a class of these numbers named for the Frenchman Mersenne. An unproven conjecture states that the number of these with a gap of “two” is infinite. Euclid showed that there are infinitely many of these numbers. For 10 points, name these non-composite numbers which are only divisible by themselves and one.

ANSWER: primes [accept any answer mentioning primes]

### Re: Specific Question Discussion

Posted: **Mon Oct 24, 2016 1:03 pm**

by **khannate**

EFT Packet 1 wrote:
6. The bootstrap method was devised as an improvement to the jackknife method for estimating this quantity for a sample. Bartlett’s test may be used to determine if a number of samples are from populations with equal values of this quantity, a condition known as homoscedasticity. For the geometric distribution, this quantity is equal to [read slowly] “one minus p over p squared.” If a continuous distribution lacks an (*) expected value, then it also lacks a value for this quantity; that is because this quantity is defined as the square of the expected value minus the expected value squared. This quantity, which is the second moment of a distribution, is equal to the square of the standard deviation. For 10 points, name this quantity that measures the amount of spread in a data sample.

ANSWER: variance [prompt on homoscedasticity until read]

I think the lead in to this tossup could afford to at least include a phrase like "most commonly used to estimate this quantity," since bootstrapping and jackknifing can both be used to approximate a bunch of things that aren't the variance. In particular, I buzzed on that clue because I knew what bootstrapping was, but then couldn't figure out what to answer with. (There's also a very minor mistake in that the variance is actually the second central moment, and not necessarily the second moment, but I doubt that'll throw anyone off.)

EFT Packet 4 wrote:
14. Samuel Yates coined the term “titanic” for examples of these values that are written in the form of 10 to the power 999 plus n, with the smallest n being equal to 7. These values raised to “p minus 1 divided by 2” are congruent to the Legendre symbol of these values over p mod p according to Euler’s criterion. A topological proof about these numbers was given by Hillel Furstenberg. Eisenstein integers with this property are (*) irreducible. Perfect numbers have a one-to-one correspondence with a class of these numbers named for the Frenchman Mersenne. An unproven conjecture states that the number of these with a gap of “two” is infinite. Euclid showed that there are infinitely many of these numbers. For 10 points, name these non-composite numbers which are only divisible by themselves and one.

ANSWER: primes [accept any answer mentioning primes]

I think the usage of the variable "p" makes the second line of this tossup a little transparent, and I heard that a few other people also felt this way. There's also a small error near the end: there's a one-to-one correspondence between Mersenne primes and

*even* perfect numbers, but I don't think it's known whether odd perfect numbers even exist.

### Re: Specific Question Discussion

Posted: **Mon Oct 24, 2016 6:36 pm**

by **Mewto55555**

The start of that primes tossup was awful. The first clue is not an important thing at all, but sure as hell sounds like it's about primes ("hmmmm what kind of number do I think 1000...07 is???). If you decide to err on the side of caution in this titanic game of chicken, you get a nonsensical clue about Euler's criterion, which, not only does it not uniquely point to primes (in fact, unless I'm misreading the clue, it applies to...every number *except * the prime p...), also frequently drops the letter p, which suggests pretty strongly that the answer isn't primes.

The Furstenberg proof is fun though!

### Re: Specific Question Discussion

Posted: **Mon Oct 24, 2016 8:02 pm**

by **John Ketzkorn**

Maybe don't have an archetype bonus part after asking for a specific archetype in an earlier round?

### Re: Specific Question Discussion

Posted: **Mon Oct 24, 2016 8:55 pm**

by **Amizda Calyx**

Furstenberg is an ergodic theorist and has therefore proved lots of things topologically (literally most of the things he's done)...for example, Szemeredi's theorem (Rutgers!), which would be a topological proof about integers.

### Re: Specific Question Discussion

Posted: **Mon Nov 28, 2016 4:28 pm**

by **Edmund**

You wrote electrochemistry (good for you!) so here's a nitpick.

Packet 8, Bonus 5 wrote:An early precursor to these devices was sketched by William Grove and soaked various metal plates in sulfuric acid. For 10 points each:

[10] Name these devices which utilize the reaction between hydrogen and water to generate energy while leaving just water as a byproduct.

ANSWER: hydrogen _fuel cells_

[10] The viability of fuel cells is considered dubious considering that hydrogen and oxygen are typically obtained from this process of splitting water with a current, which requires more energy than the fuel cell will produce.

ANSWER: _electrolysis_

[10] A common fuel cell variant uses one of these structures to separate the anode and the cathode. When hydrogen is split at the anode, electrons flow through a circuit to generate current while the remaining particles diffuse through this structure.

ANSWER: _proton exchange membrane_ [or polymer electrolyte membrane; accept PEM] <Chem, AW>

Most importantly: in the first part there's a typo "between hydrogen and water" which should read "between hydrogen and oxygen". That should be fixed if this set is being played elsewhere.

While the clues in the second part are fine, it's a bit misleading to use the fact that both electrolysis and fuel cells have < 100% efficiency to attack the hydrogen economy concept. There are plenty of reasons to consider fuel cells unviable, but it's obvious that water -> H2 -> water is going to cost energy overall; the onus, however, is on the electricity used in the electrolysis to be clean / renewable.

The third part seems a bit vague. On a re-read, I realise that the words "when" and "while" make clear that the conducted particles come from the hydrogen, but I didn't notice this when I was reading on Saturday. I think this part could easily be confused with other common, modern ion conductors that divide anode from cathode, like solid oxide or anion exchange membrane. A mention of Nafion would disambiguate.

### Re: Specific Question Discussion

Posted: **Fri Dec 02, 2016 10:05 pm**

by **Mewto55555**

Amizda Calyx wrote:Furstenberg is an ergodic theorist and has therefore proved lots of things topologically (literally most of the things he's done)...for example, Szemeredi's theorem (Rutgers!), which would be a topological proof about integers.

This is a bit of a stretch -- did you (anyone) neg this with Szemeredi/integers as a result? Furstenberg's proof of the primes is a cool trick and pretty well-known among math enthusiasts as a fun topological argument. It seems weird to assume this clue was pointing to Szemeredi's theorem when they said "topologically" as opposed to "with ergodic theory" (and if you look at his proof, it's not really topological morally; just because he's an ergodic theorist doesn't mean you'd use the word "topologically" to describe each of his proofs...). This seems like a prime example of a clue where, especially at game speed, if you actually knew what was going on, you'd buzz on it correctly, and if you didn't, you wouldn't even be baited into a neg.