Genady

I think it is for an elliptical orbit.

The horizontal axis here is some x, e.g., ellipse's major axis. The vertical axis is time. The wavy line is the orbit.

I understand that the OP question is about ontogeny of organism with a genetic disorder. What I don't understand is, what would make one to think that

This is a good summary. +1

Just like Russian! (I know it's OT.)

Got it. +1

I'd say that the basic operations are ascend/descend-by-one. Then to ascend/descend-by-two you just ascend/descend-by-one twice, to ascend/descend-by-three you ascend/descend-by-one three times, etc. To ascend/descend-by-zero you then ascend/descend-by-one zero times, i.e., you don't move. I think it is not difficult to swallow that to ascend/descend-by-(-1) you descend/ascend-by-one, to ascend/descend-by-(-2) you descend/ascend-by-two, etc.

This is one of the recurring themes in this thread, e.g.,

OK. We can use the "× -1" label to get from positives to negatives. How do we come to use the same label to get from negatives to positives?

It is not so in the grown-up's algebra, but might be a good order for learning. However, there seems to be a logical gap there: To introduce negative numbers it uses multiplication by -1, but where does the -1 come from if there are no negative numbers yet?

Ah, I see. IMO, adding and subtracting numbers do not reflect physical moving of objects but rather reflect ways of counting them.

I don't understand. The example, 4-(-6), is neither a) nor b), I think.

Then, I think, they always have a multiplicative identity, but when p is prime, they are fields, as then each element has a multiplicative inverse.

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Is 'Zp' the same as 'Z/pZ'?

Are the last three languages North Germanic while Finnish is not?

+1 (when the system lets me.) Replace that remark with, "... if you're not an electron."

I have a question. Before they start with the multiplication, after they learn only addition and subtraction of integers, do they know how to deal with, say, 4-(-6)?

The tables are often turned nowadays. The locals here usually ask visitors, "English, Espanol, Nederlands, Papiamentu?"

+1, but I've used up my daily quota. Will try to remember tomorrow. This option gives integers a ring structure.

Sorry for this impression. I went back and expressed my sincere appreciation of the inputs.

Yes, this is exactly my point, with the emphasis on "has to".

... unless you're a fermion 🙂

Sorry, the link is broken.

What you refer to is, -(-2)=2. It is not intuitive that it has to do with multiplication, i.e., (-1)*(-2)=2.