In "Good Strategy/Bad Strategy" the "Kernel" of strategy was described as containing 3 elements:

Diagnosis - Definition and explanation of the nature of the challenge faced

Guiding Policy - An overall approach to cope, address or overcome the obstacles in the Diagnosis.

Coherent Actions - Specific steps designed to carry out the Guiding Policy

in a paragraph explain what you think about Dr. Rumelt's description of the "Kernel" as the fundamental essence of a strategy. Please do not guess! You do not have to agree with the "kernel" concept, but it is valid, so think of what Dr. Rumelt is intending to say, and write about it.