L = { : t ∈ l(m) and s ∉ l(m), t,s ∈ {a,b}*, where t is the | csc520 | San Francisco State University

 L = { <M,t> : t ∈ L(M) and s ∉ L(M), t,s ∈ {a,b}*, where t is the string after s in

a lexicographic ordering of {a,b}*}. As examples, which must not appear in your proof: Let

L(M₁) = {b,aa}. Then <M₁,b> ∈ L because b ∈ L(M₁) and a ∉ L(M₁); <M₁,aa> ∉ L because both

aa and b are in L(M₁); and <M₁,a> ∉ L because a ∉ L(M₁). Prove that L ∉ D using a reduction

from H. Do not Rice’s theorem.