数学星空 发表于 2014-12-6 10:32:20

三元六次半正定条件

若设\(d_1=x+y+z,d_2=xy+xz+yz,d_3=xyz\),且\(x\geqslant0,y\geqslant0,z\geqslant0\),试找到:

\(f(x,y,z)=k_0 d_1^6+k_1 d_2 d_1^4+k_2 d_3 d_1^3+k_3 d_2^2 d_1^2+k_4 d_1 d_2 d_3 +k_5 d_2^3+k_6 d_3^2 \geqslant0\)

成立的条件,并指出\(f(x,y,z)\)取\(=\)的条件?

数学星空 发表于 2014-12-6 11:32:32

上面的问题来自于:

http://bbs.cnool.net/cthread-105590209.html

数学爱好者xzlbq给出了如下结果:

则有 \(\)

1.\(\)
2.\(\)
3.\(\)
4.\(\)
5.\(\)
6.\(\)
7.\(\)
8.\(\)
9.\(\)
10.\(\)
11.\(\)
12.\(\)
13.\(\)
14.\(\)
15.\(\)
16.\(\)
17.\(\)
18.\(\)
19.\(\)
20.\(\)
21.\(\)
22.\(\)
23.\(\)
24.\(\)
25.\(\)
26.\(\)
27.\(\)
28.\(\)

且\(f(x,y,z)\) 取\(=\)仅当\(x=y,y=kz\)成立

其中第25项中的\(0 \leqslant k _{00}\leqslant 0.03921970753\)
即满足:\(62k^6+204k^5+210k^4+200k^3+30k^2+24k-1\leqslant 0\)

上面是否给出了所有成立条件?
页: [1]
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