It says that the problem has no dual feasible solution, but what does that mean?

结果表明这个问题没有对偶的可行方案，不过这是什么意思呢？

youdao

Understand that there will be no dual tones, tri tones or quad tones held by a single mineral for upwards of 50 years.

请了解在未来50年内将没有单种矿石来掌握双重、三重和四重音调。

youdao

On level 6 you can even solo kill a fragile hero there, but basically you should have no problem against dual lanes with atro.

在6级时你甚至可以单杀掉一些脆弱的英雄，基本上用痛苦之源对付双中不会有什么问题。

youdao

If the U.S. government no longer affords dual capacity tax treatment, we can expect China to flex even more muscle, as Chevron, ConocoPhillips and Exxon Mobil are left on the sidelines.

FORBES: Obama Policy Hands China Global Energy Supremacy

Specifically, there has been no decision to ensure dual-capability in the next generation of tactical aircraft, and there is no planning for a next generation of a sea-based nuclear land-attack missile.

CENTERFORSECURITYPOLICY: Summary of the Center for Security Policy's High-l

But back then, people wanted no part of the dual headphone jacks.

FORBES: From Walkman to Facebook: How Tuning Out Led to Tuning In