Genady

It's OT, but I can't ignore the coincidence that this is the same year I got to uni.

See my later addition to the previous post.

You know that only one photon passed through because you get only one mark at a time on the second screen, say one mark a minute on average. If your setup makes it certain in any way which slit a photon went through, there is no interference. If it makes it almost certain, there is almost no interference.

It does not matter how many photons are sent out at a time: by moving your source farther away from the screen you can get the intensity at the screen as low as you wish.

Same units as for [math]E=\frac{mv^2}2[/math].

Thanks a lot for reminding me. Having the first shot tomorrow.

This is not the study's issue, but the pop-sci reporting's one. The study only says,

But this argument is wrong, at least in math: [math](A\ge B)\Leftrightarrow (A\gt B) \vee (A=B)[/math] [math](5=5)\Rightarrow (5=5)\vee (5>5)\Leftrightarrow (5\ge 5)[/math]

I've asked her about 6≥5. It was wrong, too, and you can guess the reasoning. ("6 is not equal to 5.")

I've met a math teacher once who marked 5≥5 as wrong because "5 is not greater than or equal to 5 -- it is equal to 5."

Yes, but we used to have preview, didn't we?

When I write LaTeX in my post, is there a way to preview it?

Yes, we can, but I doubt it is a significant factor.

The title question can be reversed: How far forward in time could've one understood English. Perhaps the answer to this question is much shorter than the original one.

I understand what the formulas say, but I don't understand your question (the infinity sign there is idiotic, but this is not your fault)

Where does this derivation involve the fact that the two directions are orthogonal? What would be different in this derivation if they were not?

I've guessed that this should be well known to billiard players. I, OTOH, never played billiard in my life.

Yep. Or, simply, the momentum conservation shows that the three vectors make a triangle. And then the KE conservation shows that the sides of the triangle obey Pythagoras.

Today I learned that after a moving body collides non-centrally and elastically with a body of equal mass which is at rest, they move in mutually orthogonal directions. It is quite obvious in the hindsight, but I was not aware of this.

Is it AI to blame? The movie Idiocracy has been made long before AI.

OK. Now I know what the triangle means. It's the operation XOR (exclusive OR). Let's make a diagram with [math]C\subset B[/math]: Now, let's paint the set [math]A {\Delta }B[/math]: and the set [math]A {\Delta }C[/math]: As you see, in this case [math]A {\Delta }B \neq A {\Delta }C[/math].

I don't know what that triangle sign means. Some set operation, I guess, but which? Union, intersection, subtraction...?

Consider an example. Let set W be all women and set B be all black persons. The intersection of W and B contains all black women. If a person x doesn't belong to this intersection, then x is not a black woman. x can be a black person but not a woman, a woman but not a black person, or neither a black person nor a woman.

You're talking to somebody who never came back after posting the OP.

No, it does not imply that x doesn't belong to any set. It implies that there is at least one set such that x doesn't belong to it. IOW, it does not imply that [math]x \notin A_1 \wedge x \notin A_2 \wedge x \notin A_3[/math]. It implies that [math]x \notin A_1 \vee x \notin A_2 \vee x \notin A_3[/math]. Yet IOW, it does not imply that [math]\forall i , x \notin A_i[/math]. It implies that [math]\exists i , x \notin A_i[/math].