sensitivity ·Notation:x∈{0,1n,i∈[n],Bs[n. -x:obtained from x by flipping bit i -x5:obtained from x by flipping all bits in B ·x is sensitive to i:f(x)≠f(x). ·s(f,x)={i:f(x)≠f(x)}. Sensitivity of f:s(f)=maxs(f,x). X -A measure of“smoothness”.sensitivity • Notation: 𝑥 ∈ 0,1 𝑛 , 𝑖 ∈ [𝑛], 𝐵 ⊆ 𝑛 . – 𝑥 𝑖 : obtained from 𝑥 by flipping bit 𝑖 – 𝑥 𝐵 : obtained from 𝑥 by flipping all bits in 𝐵 • 𝑥 is sensitive to 𝑖: 𝑓 𝑥 ≠ 𝑓 𝑥 𝑖 . • 𝑠 𝑓, 𝑥 = 𝑖: 𝑓 𝑥 ≠ 𝑓 𝑥 𝑖 . • Sensitivity of 𝑓: 𝑠 𝑓 = max 𝑥 𝑠 𝑓, 𝑥 . – A measure of “smoothness