[UnSA] An Integers Matrix Lemma that sometimes being forgotten

[UnSA] An Integers Matrix Lemma that sometimes being forgotten

21:53:00   UnSA,

I am going to prove the following useful lemma and wrapping the proof of inverse-adjugate formula inside my proof. I hope I put enough details on it. Lemma Let $A\in \mathbb{Z}^{n\times n}$ with $\text{det } A \neq 0$. Then there exists a unique matriks $B\in \mathbb{Q}^{n\times n}$ such...

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[Eksplorasi] Soal 1 hari pertama ON MIPA 2011

[Eksplorasi] Soal 1 hari pertama ON MIPA 2011

08:20:00   Olimpiade Matematika, ON MIPA, Univ,

Soal berikut adalah soal ON MIPA tahun 2010 hari pertama soal nomor 1 [dapet dari blog Raja Oktovin ] Saya tidak hanya akan mencoba membahas soal ini (tapi sedikit memodifikasi/memberi komentar yang berhubungan dengan soalnya, dan akan saya lakukan untuk soal-soal yang lain :D) Soal 1.  Misalkan $N$...

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Why do authors usually mix the "isomorphic" and "equal" on sign?

Why do authors usually mix the "isomorphic" and "equal" on sign?

23:47:00  

A global use of the "$A=B$"  is to denote that object $A$ is identical with object $B$. In the set theory this means that $A$ and $B$ have the same elements. But, frequently in some of Papers about Algebraic-Structure  we see some propositions like the following: 1. [Abelian...

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