General Mathematics

by **raecoffey** » Fri Aug 18, 2023 7:36 pm

I had a dream once where I became lucid, while floating around my mom's old neighborhood, so I decided to go visit everyone in their dreams. As I got to the places that I was going, I'd see that everything was different. For instance, the old restaurant 'Gitsis', on Monroe Ave, no longer existed. In its place was a bunch of palm trees

. Anyway, I was across the street from there and I was talking to a 6 year old little girl. I was explaining to her that she was only a figment of my imagination, and that she wasn't real. She immediately raised her hand, pointed her finger

, and poked herself in the eye

, and said "Ow! If I'm not real, then why did that hurt?"

by **raecoffey** » Fri Aug 18, 2023 6:40 pm

Gotcha. Now that I really think about it, I think

that I gained the ability to lucid dream, at about the same time in my life that I was suffering from chronic sleep

paralysis.

by **Casual Observer** » Fri Aug 18, 2023 12:53 pm

raecoffey wrote: Fri Aug 18, 2023 9:23 am
Casual Observer wrote: Thu Aug 17, 2023 5:28 pm
raecoffey wrote: Wed Aug 16, 2023 11:33 pm Never had serving dreams though. What were they like? Did you ever see people anything weird? Like, I don't know, Legos for breakfast ???
More like nightmares, keep getting more tables while nothing is where it should be and my POS code doesn't work, that kind of shit. Had them for like 20 years after the last time I served tables. Was so bad I taught myself lucid dreaming so I could wake myself up when it got miserable. Actually lucid dreaming is a valuable skill but hard to get consistent at, I've had luck both getting out of nightmares as well as directing the action.
How did you teach yourself to lucid dream? Just curious as I have always been able.

There was this breakthrough where I was having a nightmare and I suddenly realized it was a dream and I could wake up. When I fell back asleep almost immediately, it was the same dream but I was conscious of it being a dream and was in control of myself.

by **raecoffey** » Fri Aug 18, 2023 9:23 am

Casual Observer wrote: Thu Aug 17, 2023 5:28 pm
raecoffey wrote: Wed Aug 16, 2023 11:33 pm Never had serving dreams though. What were they like? Did you ever see people anything weird? Like, I don't know, Legos for breakfast ???
More like nightmares, keep getting more tables while nothing is where it should be and my POS code doesn't work, that kind of shit. Had them for like 20 years after the last time I served tables. Was so bad I taught myself lucid dreaming so I could wake myself up when it got miserable. Actually lucid dreaming is a valuable skill but hard to get consistent at, I've had luck both getting out of nightmares as well as directing the action.

How did you teach yourself to lucid dream? Just curious as I have always been able.

by **raecoffey** » Fri Aug 18, 2023 9:22 am

The thing about math dreams is that they can get really abstract. Taking the Jacobian on people meant that I was reducing them to their two dimensional counterparts, for one thing.

by **Casual Observer** » Thu Aug 17, 2023 5:28 pm

raecoffey wrote: Wed Aug 16, 2023 11:33 pm Never had serving dreams though. What were they like? Did you ever see people anything weird? Like, I don't know, Legos for breakfast ???

More like nightmares, keep getting more tables while nothing is where it should be and my POS code doesn't work, that kind of shit. Had them for like 20 years after the last time I served tables. Was so bad I taught myself lucid dreaming so I could wake myself up when it got miserable. Actually lucid dreaming is a valuable skill but hard to get consistent at, I've had luck both getting out of nightmares as well as directing the action.

by **raecoffey** » Wed Aug 16, 2023 11:33 pm

Never had serving dreams though. What were they like? Did you ever see people anything weird? Like, I don't know, Legos for breakfast

???

by **raecoffey** » Wed Aug 16, 2023 9:03 pm

I used to be a waitress at Marks Texas Hits on the overnight shift. So when all of those bars closed on Monroe Ave at 2am, their drunk, loud, pissy, disrespectful asses would pour into the restaurant.

by **Casual Observer** » Tue Aug 15, 2023 8:45 am

Ow, my head hurts from just skimming that. Impressed. The only workish treams I ever had were "waiter dreams" (ask anyone who has waited tables for any decent length of time what they are).

by **raecoffey** » Tue Aug 15, 2023 12:01 am

I must have been half asleep when I wrote that, but I see where I was. Going with it.

In the same way as multiplication is a process that you can apply to a function, the Jacobian is a process that you apply to a system of equations, also known as a matrix.

by **raecoffey** » Mon Aug 14, 2023 11:59 pm

*edit, a Jacobian is NOT applied to a function, but to a matrix only.

by **raecoffey** » Mon Aug 14, 2023 11:57 pm

by **raecoffey** » Mon Aug 14, 2023 11:54 pm

I went to grad school for Applied Mathematics, and sometimes, I do a lot of math in my dreams, and I just wanted to share one with you guys.

I don't know how far you got in math, Do you remember equations?
Well a matrix is a system of equations. And in much the same way as you can apply a function to a function, by, say, multiplying one by the other, like 3f x 2b, you can also apply a matrix to a matrix. And in much the same way as multiplication

is a process that you apply to a function, a Jacobian, is also applied to a function, just with different, more complex rules. Anyway, in my dream, I was taking the Jacobian on people.

I'll post an example of Jacobian matrices in the next post...

by **Mama Blue** » Fri Apr 21, 2023 5:23 pm

Yes Tdarcos, you've got it.

by **Tdarcos** » Fri Apr 21, 2023 4:45 pm

I think someone said, "The more I learn the more I discover there is to learn." And today I discovered, in part, just how wide just my own chasm of ignorance is, and I consider myself an educated person.

The American Mathematical Society, no less, has created a book 227 pages long, (PDF here) and what it does is, lists is all of the topics of mathematics, plus two pages on how to use the classification list, so that if you're writing an article for publication in their Journal, you put it in one (or more) of the two thousand subject classifications. I mean, 227 pages and all it is is just the list of subjects in mathematics; it doesn't even begin to describe them.

There are more than 50 major topics, numbered from 00 to 97. Each major topic can have up to 27 sections, with -, or lettered A to Z. Then each section has up to 100 related subjects, numbered from 00 to 99, with 00, when used, for general works in that section, and 99, when present, reserved for "none of the above, but in this section."

Just for flavor, I'll pick 10 topics.
00 General and overarching topics; collections
03 Mathematical logic and foundations
19 K-theory
34 Ordinary differential equations
41 Approximations and expansions
42 Harmonic analysis on Euclidean spaces
43 Abstract harmonic analysis
68 Computer science
74 Mechanics of deformable solids
76 Fluid mechanics

Let's look at #68. Computer Science.
68-XX Computer science
- 68-04 Software, source code, etc. for problems pertaining to computer science
68Nxx Theory of software
-68N15 Theory of programming languages
68Pxx Theory of data
-68P05 Data structures
-68P10 Searching and sorting

You get the idea. This one topic has 10 sections, and a total of 110 subjects. Of these 110 my guess is I'm probably very familiar with 3 or 4, have some familiarity with 5 or 6, and maybe have heard of 10. That leaves 90 subjects in my own field I have neither knowledge nor understanding.

by **Tdarcos** » Fri Apr 21, 2023 3:44 pm

pinback wrote: Thu Apr 20, 2023 3:50 am
Tdarcos wrote: Thu Apr 20, 2023 3:15 am I had not seen anything from you.
You didn't see that giant mother christing image at the top of the page?

No, I did not. In case you have forgotten, sometimes new message search misses items, sometimes I do.

by **pinback** » Thu Apr 20, 2023 3:50 am

Tdarcos wrote: Thu Apr 20, 2023 3:15 am
Mama Blue wrote: Wed Apr 19, 2023 8:17 pm
Jizaboz wrote: Wed Apr 19, 2023 8:15 pm Wah wah wahhhh

It's fucking Paul replying HIMSELF in your thread! Were you REALLY expecting a different outcome?

Also, I read the question last night but couldn't even come up with a guess so there is that.
Lol it was a rhetorical complaint. And yes, it was meant for Paul replying to himself.
I was not talking 'over' you, I had not seen anything from you.

You didn't see that giant mother christing image at the top of the page?

by **Tdarcos** » Thu Apr 20, 2023 3:15 am

Mama Blue wrote: Wed Apr 19, 2023 8:17 pm
Jizaboz wrote: Wed Apr 19, 2023 8:15 pm Wah wah wahhhh

It's fucking Paul replying HIMSELF in your thread! Were you REALLY expecting a different outcome?

Also, I read the question last night but couldn't even come up with a guess so there is that.
Lol it was a rhetorical complaint. And yes, it was meant for Paul replying to himself.

I was not talking 'over' you, I had not seen anything from you.
If you're referring to the reference to the chapter on linear algebra, I had never seen these symbols before; this is not an introductory text and it will take time to absorb.
If you're referring to Cherryl's birthday, I did not see it until now. That, I will now take a look at,

Both know one piece of information. Looking at the list, we need to know what's when, so let's sort side by side

14 july
14 august
15 may
15 august
16 may
16 july
17 june
17 august
18 june
19 may

I think I see it. First, drop the months that have unique dates, because if he has a unique day, you know the month. The 19th is unique to May, so drop May because if it was the 19th, you'd know it was in May

14 july
14 august
15 august
16 july
17 june
17 august
18 june

If it was the 15th, it's August so it's gone

14 july
16 july
17 june
18 june

Now, I'm a bit stumped. Now, I think you go from the month.
Let's try this: Wharever month you have, you eliminate the months that have the same days.
If he knew the month was july, it had to fall on the 14th or the 16th, both are shared with a month later eliminated. (August 14, May 16).
If he knew it was June, day must be 17 or 18. August 17 is eliminated, so I get

June 18

by **RealNC** » Thu Apr 20, 2023 3:02 am

I've seen this problem before. It's not strictly a math problem, and a big issue with the original phrasing of it is that it's been written by a non-native English speaker and the statements make it look like there's some kind of clues between Albert (communicating the number 2 to Bernard) and Bernard (passing the the number 1 to Albert.) There isn't, and lots of people waste a lot of time assuming there is.

All you need to know to solve the problem are the 10 possible dates, that one of the guys knows the month, the other knows the day, and their statements about whether they now know or not.

I wasn't able to solve it, but once you see the solution you go "duh!" Especially if you wasted your time assuming the two guys were giving clues to each other.

by **Mama Blue** » Wed Apr 19, 2023 8:17 pm

Jizaboz wrote: Wed Apr 19, 2023 8:15 pm Wah wah wahhhh

It's fucking Paul replying HIMSELF in your thread! Were you REALLY expecting a different outcome?

Also, I read the question last night but couldn't even come up with a guess so there is that.

Lol it was a rhetorical complaint. And yes, it was meant for Paul replying to himself.

General Mathematics

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