[johnu]

 aguahombre, on 2016-January-07, 22:56, said:

Ok. Bring it on; announce 15-17, which obviously means you open 15 or 16 only. Then please explain how the misinformation is mathematically correct, and it is the ACBL's fault for the confusion.

You announce 15 to 17. In what country does this mean 15 or 16? Everybody I know would correctly interpret this as 15, 16 or 17. I suggest you google "range" and clear up you confusion.

[sfi]

 johnu, on 2016-January-08, 00:00, said:

You announce 15 to 17. In what country does this mean 15 or 16? Everybody I know would correctly interpret this as 15, 16 or 17. I suggest you google "range" and clear up you confusion.

We get it - English is not as precise as mathematical terminology. Nonetheless, everyone else seems to understand the meaning of range in this context with no difficulty. The regulations may be easier to navigate if you don't try so hard to misconstrue their intent.

[johnu]

 sfi, on 2016-January-08, 00:05, said:

We get it - English is not as precise as mathematical terminology. Nonetheless, everyone else seems to understand the meaning of range in this context with no difficulty. The regulations may be easier to navigate if you don't try so hard to misconstrue their intent.

Everyone else is a huge overbid and the question about range seems to come up fairly frequently so there apparently is some difficulty in divining the intent of the chart drafters.

[aguahombre]

 johnu, on 2016-January-08, 00:00, said:

You announce 15 to 17. In what country does this mean 15 or 16? Everybody I know would correctly interpret this as 15, 16 or 17. I suggest you google "range" and clear up you confusion.

Make up your mind; yes, it is a 3 point range. You argue that 10-15 is a five point range in your language of math, then decide it is different when I point out the absurdity of 15-17 being a 2-point range.

[helene_t]

It is true that 15.000 - 10.000 = 5.000 but that is completely irrelevant.

If we consider point counts to be discrete then Card{10,11,12,13,14,15}=6.

If we consider point counts to be rounded-off numbers based on an underlying continous scale then 15.5-9.5=6.0

If 10-12 and 13-15 are considered adjacent intervals then for any measure (call it "cardinality", "length" or whatever you like) it should apply that the size of the 10-15 interval equals the sum of the sizes of 10-12 and 13-15. Claiming that 10-12 and 13-15 are both 2-point ranges while 10-15 is a 5 point range is equivalent to 2+2=5.

I don't think ACBL needs to explain the obvious. There may be hundreds of unclear points in ACBL's official documents but this is not one of them.

[nullve]

I agree with what helene_t said, except that I think she forgot to mention that 'range' is also used (esp. in her field, statistics) in the sense of a difference between extreme values, in which case range of the set {10,11,12,13,14,15} is 15-10=5, not 6. So I can sort of understand the confusion.

[PeterAlan]

 johnu, on 2016-January-07, 17:06, said:

 RMB1, on 2016-January-07, 16:24, said:

In mathematics, a range is set, not a number. When we assign a number to a range it is its size or length. If HCP are real numbers, then the range "10-15" is the interval [10.0, 15.0] which has length 5.0. If HCP are whole numbers, then the range "10-15" is the set {10, 11, 12, 13, 14, 15}; this set does not have a length but it has size (cardinality) 6.

Look up the definition of range as it pertains to math to see where you are wrong.

Robin is someone who studied mathematics to doctorate-candidate level at arguably the strongest mathematics faculty in the UK, and knows whereof he speaks. There is more to the subject than definitions from MathGoodies. This kind of gratuitous rudeness is out of order.

Peter

[barmar]

 sfi, on 2016-January-08, 00:05, said:

We get it - English is not as precise as mathematical terminology. Nonetheless, everyone else seems to understand the meaning of range in this context with no difficulty. The regulations may be easier to navigate if you don't try so hard to misconstrue their intent.

I suspect that very few people even think about it, because hardly anyone plays a NT range that's large enough for it to matter what definition is used. Whether 15-17 is 2 or 3 is irrelevant when the regulation only cares about 5 or more. The only people who need to worry about the definition of "range" are those playing something like 10-15 NT. I don't think I've ever encountered something like that until this thread.

[barmar]

 jeffford76, on 2016-January-07, 12:55, said:

The part on the GCC about "including those that have non-consecutive ranges" means that for this purpose your range is 10-21, a 12 point range (not 11), so conventions would not be allowed.

How do you get that? If it's high-low it's 11. If it's the number of possible HCP values, it's 4 (10, 11, 20, 21). I don't see why you should count all the HCP values in the gap between the two ranges if you're using cardinality as the definition.

[jeffford76]

 barmar, on 2016-January-08, 09:22, said:

How do you get that? If it's high-low it's 11. If it's the number of possible HCP values, it's 4 (10, 11, 20, 21). I don't see why you should count all the HCP values in the gap between the two ranges if you're using cardinality as the definition.

In that case it doesn't matter anyway. The point was that the regulation is intended to prohibit conventions over something like 10-12 or 16-17. I believe it's also intended to prevent 10-11 or 14-15 (counting it as a six point range), but I don't have any special document I can point to for that.

[blackshoe]

 jeffford76, on 2016-January-08, 12:12, said:

In that case it doesn't matter anyway. The point was that the regulation is intended to prohibit conventions over something like 10-12 or 16-17. I believe it's also intended to prevent 10-11 or 14-15 (counting it as a six point range), but I don't have any special document I can point to for that.

Neither, I suspect, would anyone in Horn Lake, if you asked them.

[Shugart23]

I actually think ken might have a valid point. If 10 to 13 is allowed if white and 13 to 15 is allowed if not whitr and this scheme is not considered a 6 point range, then just change the words white and not white to be hearts and no hearts. What is the difference?

[Vampyr]

 Shugart23, on 2016-January-09, 08:20, said:

I actually think ken might have a valid point. If 10 to 13 is allowed if white and 13 to 15 is allowed if not whitr and this scheme is not considered a 6 point range, then just change the words white and not white to be hearts and no hearts. What is the difference?

LOL not sure you could fool even the thickest director with this argument!

[jnichols]

 Shugart23, on 2016-January-09, 08:20, said:

I actually think ken might have a valid point. If 10 to 13 is allowed if white and 13 to 15 is allowed if not whitr and this scheme is not considered a 6 point range, then just change the words white and not white to be hearts and no hearts. What is the difference?

The difference is that everyone in the room can tell which of white or not white apply. The announcement should either be "10-13" or "13-15", not some combination. On the other hand if its hearts or no hearts no one except the opener knows which one applies. And that is a huge difference.

[Shugart23]

And yet the 'rule' doesnt make this distinction so this is perhaps your interpretation of the rule and not the literal reading of it. But yeah, its out of the box and probably a stretch

[campboy]

 Shugart23, on 2016-January-09, 09:56, said:

And yet the 'rule' doesnt make this distinction so this is perhaps your interpretation of the rule and not the literal reading of it. But yeah, its out of the box and probably a stretch

Of course it does. You're not allowed to play conventions after "natural notrump opening bids [...] with a range of greater than 5 HCP". If you open 1NT, not vul, all that matters is the range of that particular opening bid, and 10-13 is fine. The fact that a different notrump opening bid might have a different range is irrelevant -- just as irrelevant as the fact that in standard a notrump opening could be 15-17 or 20-22 depending on what level it is at (the regulation doesn't say anything specifically about 1NT, after all).

[gwnn]

Can't believe that nobody called out this blatant racism in this thread.

(sorry, couldn't help myself.)

[jallerton]

 RMB1, on 2016-January-07, 16:24, said:

In mathematics, a range is set, not a number. When we assign a number to a range it is its size or length. If HCP are real numbers, then the range "10-15" is the interval [10.0, 15.0] which has length 5.0. If HCP are whole numbers, then the range "10-15" is the set {10, 11, 12, 13, 14, 15}; this set does not have a length but it has size (cardinality) 6.

 johnu, on 2016-January-07, 17:06, said:

.

Look up the definition of range as it pertains to math to see where you are wrong.

 PeterAlan, on 2016-January-08, 05:07, said:

Robin is someone who studied mathematics to doctorate-candidate level at arguably the strongest mathematics faculty in the UK, and knows whereof he speaks. There is more to the subject than definitions from MathGoodies. This kind of gratuitous rudeness is out of order.

Peter

True, Robin is an expert in mathematics, but Robin's studies may not have extended to anything called "math".

[Shugart23]

 campboy, on 2016-January-09, 12:55, said:

Of course it does. You're not allowed to play conventions after "natural notrump opening bids [...] with a range of greater than 5 HCP". If you open 1NT, not vul, all that matters is the range of that particular opening bid, and 10-13 is fine. The fact that a different notrump opening bid might have a different range is irrelevant -- just as irrelevant as the fact that in standard a notrump opening could be 15-17 or 20-22 depending on what level it is at (the regulation doesn't say anything specifically about 1NT, after all).

I know what you are saying. I can still also see kens argument that opening 1nt in the heart/no heart scenerio is indeed a 3 point range. It is just that nobody knows which range it is until the rebid. Having said that, i am not going to try it !

[helene_t]

You could also try:

12-14 if I have less than 15 points
15-17 otherwise