arrow, double (): a symbol used to indicate a change that is more complete or comprehensive than that which is signalled by the single arrow (). Generally, the change's complete structural description (the segments that change, with the entire context or environment necessary) is included to the left of the arrow, and on the right of the arrow are repeated those same elements as they exist after the change. For example, A B C  Ø C B means that, given elements A, B, and C, in that order, A is deleted and the other two elements are transposed so that C precedes B. Sometimes this arrow is written ==>, using only symbols that are available on most keyboards. [Spanish: flecha doble]