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bio website math.jussieu.fr/~leila/…
location Lhasa, Tibet
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seen Mar 19 '13 at 2:45

We choose to do mathematics, not because it is easy, but because it is hard.

$$ \text{Einstein's Field Equations:} \quad \mathbf{G} = \frac{8 \pi G}{c^{4}} \mathbf{T}. $$


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comment Norms involving positive operators
A simple counterexample comes from $ -2I \leq I $. Of course, if both $ A $ and $ B $ are required to be positive, then a counterexample is a little harder to find.
Mar
19
comment Norms involving positive operators
@julien: I think saying that $ A \leq B $ requires both $ A $ and $ B $ to be at least self-adjoint operators.