lentic catachresis
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 Oct18 awarded Yearling Oct12 comment Particular case of Nakayama's lemma @Jack Ah, I see. Using elements as I was doing, it's $m=an_1\in M \Rightarrow m=a^2n_2\in M \Rightarrow \dots \Rightarrow m=a^kn_k=0$. Thank you. Oct12 asked Particular case of Nakayama's lemma Oct10 comment Isn't it cheating to consider an $\mathbb{R}^3$ vector as a “pure quaternion”? @Mariano: what is MU? Oct1 comment Square roots of $-1$ in quaternion ring Ouch, I found my mistake. I must remember that the binomial theorem only works in commutative rings. Thank you! Oct1 asked Square roots of $-1$ in quaternion ring Sep28 comment What makes simple groups so special? Sep28 answered Why is any compact metric space the union of a countable set a subset which is a perfect space under the induced topology? Sep27 comment Why is any compact metric space the union of a countable set a subset which is a perfect space under the induced topology? Sep19 comment Is there a more efficient method of trig mastery than rote memorization? @GiuseppeNegro: I think you should expand your comment into an full-fledged answer, expanding on your claim. I would certainly vote you up ;) Sep16 comment free $R$-algebras: when does $R\langle X\rangle\cong\!R\langle Y\rangle$ $\Rightarrow$ $|X|\!=\!|Y|$ hold? +1 for a well-posed, motivated question. Sep11 comment Motivation for Eisenstein Criterion @Qiaochu: In Gallian's book, he states the "Mod p irreducibility test" with an additional hypothesis, which is that the reduced polynomial mod $p$ must have the same degree as the original polynomial in $\mathbb{Z}$ for the implication "irreducible over $\mathbb{Z}_p\Rightarrow$ irreducible over $\mathbb{Q}$" to work (and it seems an important point to the proof). Why don't you require it? Can it be proven without that hypothesis? Sep11 comment Showing $\sup \{ \sin n \mid n\in \mathbb N \} =1$ Sep8 comment Methods to see if a polynomial is irreducible ...if $a$ is a unit. Sep7 comment What's the index of a subfield? As a comment, I'd like to point out that using the same notation for different notions (degree of a field extension and index of a subgroup) is useful, the Galois correspondence theorem being its prime evidence. Sep7 answered Finding $\lim\limits_{x \to \infty} \sqrt{9x^2+x} - 3x$ Sep4 awarded Nice Question Sep4 revised What's bad about left $\mathbb{H}$-modules? added 233 characters in body Sep3 comment Quotient objects, their universal property and the isomorphism theorems Thank you for your answer. What about considering a category with zero morphisms and normal monomorphisms? This would cover at least the category of groups. At any rate I'm still not fully satisfied, as per your comment on your last paragraph... maybe category theory is not the right language to express what is at hand? Sep2 revised What's bad about left $\mathbb{H}$-modules? added 307 characters in body