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-2 votes
2 answers
260 views

For any numbers $a, b,$ and $c,$ $a + b = a + c$ if and only if $b = c$ [duplicate]

I was reading about the field of real numbers $\mathbb{R},$ and a basic question arose in my mind. How one should prove that, for any numbers $a, b,$ and $c,$ $a + b = a + c$ if and only if $b = c?$ ...
Air Mike's user avatar
  • 3,794
1 vote
2 answers
104 views

Proof that $\frac{1}{2} + \frac{1}{2} = 1$ using just the algebraic properties of $\mathbb R$

Like the title says, can you prove rigorously that $\frac{1}{2} + \frac{1}{2} = 1$ using only the nine field properties of $\mathbb R$? I don't know if addition and multiplication are supposed to be ...
Tim's user avatar
  • 817
3 votes
1 answer
206 views

Abstracting Magnitude Measurement Systems (i.e. subsets of ${\mathbb R}^{\ge 0}$) via Archimedean Semirings.

I did some googling but could not find any easily accessible theory so I am going to lay out my ideas and ask if they hold water. Definition: A PM-Semiring $M$ satisfies the following six axioms: (1)...
CopyPasteIt's user avatar
  • 11.5k