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Jan 25 at 6:49 vote accept joro
Jan 17 at 16:26 answer added Peter Taylor timeline score: 2
Jan 17 at 11:57 comment added joro @PeterTaylor Many thanks, I edited about 1.
Jan 17 at 11:56 history edited joro CC BY-SA 4.0
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Jan 17 at 9:41 comment added Peter Taylor 1 isn't a zero divisor. That quibble apart, see mathoverflow.net/questions/42647/… for examples.
Jan 17 at 9:33 comment added joro @YCor Thanks. Do you know another commutative ring or algebra where every element is zero divisor?
Jan 17 at 8:40 comment added Dave Benson $x^2-x=x(x-1)$ so by Chinese remainders, $\mathbb{F}_2[x]/(x^2-x)$ is $\mathbb{F}_2[x]/(x) \times \mathbb{F}_2[x]/(x-1)$, which is $\mathbb{F}_2 \times \mathbb{F}_2$. So you're tensoring together $n$ copies of this, to get a ring isomorphic to a direct product of $2^n$ copies of $\mathbb{F}_2$. Yes, it has cardinality $2^{2^n}$.
Jan 17 at 8:11 comment added YCor Yes, the free Boolean algebra on $n$ generators has dimension $2^n$ (thus cardinal $2^{2^n}$).
Jan 17 at 8:10 history edited YCor
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Jan 17 at 8:01 history asked joro CC BY-SA 4.0