ε ⋅ s = s ⋅ ε = s. The empty string is the identity element of the concatenation operation. The set of all strings forms a free monoid with respect to ⋅ and ε. ε R = ε. Reversal of the empty string produces the empty string. The empty string precedes any other string under lexicographical order, because it is the shortest of all strings.
Bob Woolmer (1948–2007): English international cricketer, professional cricket coach and commentator, playing in 19 Test matches and 6 One Day Internationals for England and later coaching South Africa, Warwickshire and Pakistan. Video games. David Cage (1969–): French video game designer, writer and musician.
He lives in Stevenage, Hertfordshire, with his wife Barbara, the former Labour Member of Parliament for Stevenage. Between them they have five children, six grandchildren and two Labradors. Then the Fassung of the content of a book in itself can differ vastly, as can be observed in the different reviews of one book on Goodreads alone.