Let x and y be strings and let L be any language. We say that x and y are distinguishable by L if some string z exists whereby exactly one of the strings xz and yz is a member of L; otherwise, for every string z, we have xz 2 L whenever yz 2 L and we say that x and y are indistinguishable by L. If x and y are indistinguishable by L, we write x L y. Show that L is an equivalence relation.

Which sentences describe the things you need to ensure while creating a sketch and a drawing? while an artistic or creative drawing is a creative expression, a technical drawing is an informative expression. you need to create accurate and neat drawings to convey accurate information. a technical drawing clearly conveys its meaning or information, and does not leave room for interpretation maintain a good speed while creating drawings