"Functional?"
Ilana softly repeated this unfamiliar term, her clear eyes filled with curiosity and a quest for the unknown.
"That's right."
Luo Yan's voice was gentle and clear. To help his genius apprentice better understand the mysteries of the functional, he used an easy-to-grasp analogy.
"Ilana, do you remember what we learned about 'Calculus'? What is its core purpose?"
Ilana answered without hesitation.
"It's to study the rate of change of functions and to find the extreme values of functions. For instance, finding the highest point of a mountain peak or the lowest point of a valley."
"Exactly right." Luo Yan nodded approvingly. "Calculus tells you at which 'point' you can stand the highest or lowest. But a 'functional' addresses a completely different issue."
He took out his magic wand and gently waved it, drawing a gentle curve in the air, followed by a steep one.
