1. understood that symbol string and set operations.
L={A,B, … ,Z,a,b, … ,z}
D={0,1, … ,9}
L and D can be seen as the alphabet, L and D can also be seen as language
Description meaning under represented:
LUD: full set of letters and numbers
LD: the set of all strings of symbols consisting of a letter followed by a number composed of
L4: the set of all strings of symbols of four-letter
The set of all symbol string of letters (including [Sigma) is: L *
D +: the set of all strings of symbols by one or several digits
The set of all strings beginning with the letter symbol, followed by the letter, numbers of: L (LUD) *
2. grammar G (Z): Z-> aZb | ab definition of what kind of language?
Production has: Z-> aZb, Z-> ab
Can be deduced: Z-> ab
Z->aZb->aabb
Z->aZb->aaZbb->aaabbb
.........
And so on, can be obtained on a L (G [the Z]) = {a n- b n- | ≧ n-a}. 1, a and b equal to the number of language grammar.
3. Write grammar quaternion form materials 22 pages in Example 2.2 identifier (VN, NT, P, S).
Where V N = {the I, L, D}, V T = {L, D}
P={ I -> I | IL | ID
L -> a | b | c | .....| x | y | z
D -> 0 | 1 | 2 | .....| 9}
S= I
4. Write the following expressions leftmost derivation, rightmost derivation.
G (E):
E=> E + T | T
T=>T * F | F
F=>（E）| i
- i*i+i
最左推导：E => E + T => T + T => T * F +T => F * F +T => i * F +T => i * i +T => i * i + F => i * i + i
最右推导：E => E + T => E + F => E + i => T + i => T * F + i => T * i + i => F * i + i => i * i + i
- i+i*i
最左推导：E => E + T => T + T => F + T => i + T => i + T * F => i + F * F => i + i * F => i + i * i
最右推导：E => E + T => E + T * F => E + T * i => E + F * i => E + i * i => T + i * i => F + i * i => i + i * i
- i+(i+i)
最左推导：E => E + T => T + T => F + T => i + T => i + F => i + (E) => i + ( E + T ) => i + ( T + T ) => i + ( F + T ) => i + ( i + T ) => i + ( i + F ) => i + ( i + i ）
最右推导：E => E + T => E + F => E + ( E ) => E + ( E + T ) => E + ( E + F) => E + ( E + i ) = > E + ( F + i ) => E + ( i + i ) => T + ( i + i ) => F + ( i + i ) => i + （ i
+ i）