kernel of a morphism

例句：

1. 1.The kernel of the problem is that we need to find a solution.
   问题的核心是我们需要找到一个解决方案。
2. 2.The kernel of the new policy is its emphasis on education.
   新政策的内核是其对教育的强调。
3. 3. The kernel of the cake is the frosting.
   蛋糕的内核是糖霜。