## inequality – Calculates the minimum value of \$ sum_ {cyc} frac {a ^ 2} {b + c} \$ where \$ a, b, c> 0 \$ and \$ sum_ {cyc} sqrt {a ^ 2 + b ^ 2} = 1 \$.

$$a$$, $$b$$ and $$c$$ are positive such as $$sqrt {a ^ 2 + b ^ 2} + sqrt {b ^ 2 + c ^ 2} + sqrt {c ^ 2 + a ^ 2} = 1$$. Calculate the minimum value of $$large frac {a ^ 2} {b + c} + frac {b ^ 2} {c + a} + frac {c ^ 2} {a + b}$$

I do not have any ideas yet to solve the problem. I will probably do it in the near future, but for now, I can not.

## probability – Assume that \$ A \$ and \$ B \$ are independent events. For a \$ C \$ event such as \$ P (C)> \$ 0, prove that \$ A \$ event donated \$ C \$

assume $$A$$ and $$B$$ are independent events. For an event $$C$$ such as $$P (C)> 0$$ , prove that the event of $$A$$ given $$C$$ is independent of the event of $$B$$ given $$C$$

We have A and B are independent so $$P (AB) = P (A) cdot P (B)$$

We must show that $$P ((A mid C) cap (B mid C)) = P (A mid C) cdot P (B mid C)$$

My procedure was like that
$$P ((A mid C) cap (B mid C)) = P ((A mid C) mid (B mid C)) cdot P (B mid C)$$
$$= frac {P (AB mid C)} {P (B mid C)}$$

I played until I got this
$$frac {P (AC)} {P (C)} cdot frac {P (B mid AC)} {P (B mid C)}$$
Now the first part gives us $$P (A mid C)$$ . I could not get from the second part the missing part that is $$P (B mid C)$$.

Is my procedure correct? If so, how can I find the second part?

## Need an algorithm to determine if the expressions A> B> C> D are legal

I need to set the priority of the parameters of the function, such as the function `Func (A, B, C, D, E)`
Others can write rules to set this priority. I need an algorithm to check if this rule is legal or not. I do not know which keywords should I search on Google?
`A> B> C> D> E` is legal.
`A> B> C> A` it's not legal.
`A> (B && C && D)> (B && C)> E` is legal.
`A> (B && C)> (B && C && D)> E` it's not legal.