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areyousure

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I have wanted one general application of this idea in a spreadsheet. Specifically, I track some of my running, including speed (pace), distance, and time. Under different circumstances, I have exactly two of the three available and I want the third to be computed, but it varies which. I have found it fairly difficult to implement this kind of data entry in Google Spreadsheets and Excel, even know conceptually it's a very simple constraint "a*b=c" where I know some two variables.

As a more substantive comment: You may find the thesis "Propagation networks : a flexible and expressive substrate for computation" by Alexey Radul interesting. https://dspace.mit.edu/handle/1721.1/54635

Ask four mathematicians whether something is a Commutative Ring or not and they'll all agree.

Amusingly, there are at least 3 different definitions of commutative ring.

The principal issue is whether it must have a 1 (unity, ie a multiplicative inverse). Wikipedia https://en.wikipedia.org/wiki/Commutative_ring as well as most modern sources insist on this.

Britannica https://www.britannica.com/science/ring-mathematics#ref89421... as well as many older sources (such as Noether's original definition and van der Waerden) do not insist that the ring have a 1. Even first-edition Bourbaki didn't have 1!

Finally, if you do have a 1, then sometimes people include the condition that 0 != 1, ie the trivial/zero ring is deemed not a [commutative] ring. This is somewhat hard to find, but is relatively common among people who specifically define the concept of "ring with identity" (eg Zariski+Samuel). I have also found it unqualified (ie, just in the definition of "commutative ring") in the wild, eg in "Handbook of Mathematical Logic" by Barwise or "The Math You Need" by Mack.

(I agree with people like Conrad and Poonen that rings should have a 1. And I guess that the zero ring is in fact a [commutative] ring.)

Suppose we designate a unit line segment, and from that we pick out a line segment of (what we now call) length 2 and separately a rectangle of area 3. To "an ancient" (like Aristotle), does it make sense to add the length and the area to get 5? If you then drew a line segment of length 5, would they say it has the same magnitude?

(My understanding is "no" to both questions.)

Sadly, firms abuse odd lot rules to give people terrible prices: https://academiccommons.columbia.edu/doi/10.7916/2y01-1s13/d...

In example 3, the NBBO for stock ABC is 495--500, but there is also an odd lot offer for 497 on exchange. If a Robinhood customer sends a market buy order, then Citadel is allowed to fill it for 499.999 even though it's better to send to the exchange. (And if they then pick up the odd lot themselves, it's easy arbitrage.)

By the way, while you're correct about some of your claims, odd lot executions definitely have to occur within the NBBO. (How could it be otherwise?) Otherwise, in the example above, Citadel would give an even worse price!

In case anyone was curious, I computed some popular margins of victory defined as (%popular vote of winner) - (%popular vote of highest other candidate).

I got the following small margins of victory smaller than the 1.5% in 2024, five of which are positive and five of which are negative.

-7.8% in 1824, 1.4% in 1844, -3% in 1876, 0% in 1880, 0.6% in 1884, -0.8% in 1888, 0.1% in 1960, 0.7% in 1968, -0.5% in 2000, -2.1% in 2016.

In case anyone was curious, the interest being paid on the national debt is of the order of $1 trillion per year, while the amount collected in taxes (federally only) is of the order of $5.5 trillion per year.

Your number "3.5%" refers to US military spending as a proportion of GDP.

The original number "5%" refered to NASA spending as a proportion of the federal budget.

These baselines currently differ by approximately a factor of 4.

I think one of the reasons people might be harping on you is because the "Special military operation" started on 2022 February 24, which is 652 days < 1.8 years ago. In particular, even after you add 6 weeks to it, it's still less than 2 years.

I assume you mean T + 6 weeks, where T is the time since the invasion and T is approximately 2 years, even though T + 6 weeks is still less than 2 years?

The wikipedia page for the shootdown incident [4] lists the time as 1349 GMT.

In case anyone is curious, the Wikipedia page mention of this time is as follows: "at 13:49 UTC (49 minutes after take-off), KAL 007 reported that it had reached its Bethel waypoint". Bethel is a city in the U.S. state of Alaska.