Is zero a natural number?

[Carl Hickey]

Computer scientists and set theorists start counting at 0. Most other people start counting at 1.

But, in set theory, 0 is a natural number and is identified with the empty set, just like 1 is identified with the set containing just the empty set.

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= = =

Lateral (complex) numbers: oriented line segment (vector, 1 d) in a plane (2 d).

a (length, angle), b (length, angle)

c = a . b (length (a) . length (b), angle (a) + angle (b))

-

(-2) . (-3) = 6 (2 . 3, pi/180 + pi/180 = 2 pi/360/0)

i (1, 90)

i . i = -1 (1 . 1, 90 + 90 = 180)

= = =

Natural numbers were created by God, everything else is the work of men.
Kronecker (1823–1891).

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In the beginning was the Word, and the Word was with God, and the Word was God. He was with God in the beginning. Through Him all things were made, and without Him nothing was made that has been made. In Him was life, and that life was the light of men. The Light shines in the darkness, and the darkness has not overcome it.

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/word ~ logos ~ wisdom ~ .../

Gospel of John

Hi,

On YouTube there is a video made by a young mathematician. He uses cardboard boxes (empty boxes in boxes) to visualise the idea.
I'll place the link after my 30th post here.