δ is similar to a mathematical function called the transition function. Something like.
z = f(x, y)
A function in mathematics determines the mapping of elements in one set to another set. The function set of input arguments is called Domain of function, and the output is fury.
[ANSWER]
In the expression "δ:Q×Σ → Q" ,
× means a Cartesian product (this is a set), and → is a mapping .
> "δ:Q×Σ → Q" says that δ is a transition function that defines a mapping from Q×Σ to Q Where, the region δ is Q × Σ , and Range is Q
Note: A Cartesian product in itself is mathematical, that all possible pairs (mapping) are between two sets.
You can also say:
δ is the transition function that determined the mapping between (or, say, associates) the Cartesian product of the set of states Q and the language symbols Σ into the set of states Q This is abbreviated as δ: Q × Σ → Q
Here Q is a finite set of states, and Σ is a finite set of language symbols.
In addition, in any automatic mode, you can present the transition function in the form of a tree.
1. Transition table
2. Transition graph or indicate a state diagram.
3. Transition function : a finite set of display rules. for example { δ(q0, a) → q1 , δ(q1, a) → q2 }
Everything for this purpose defines maping.
In the DFA. δ:Q×Σ → Q can also be written as δ(Q,Σ) → Q It looks like a function. In the function δ two input arguments are the state Q and the language symbol Σ , and the return value is Q
What does δ(Q,Σ) → Q mean δ(Q,Σ) → Q
Suppose that in your set of transition function δ you have an element δ(q0, a) → q1 . If the current state is q0 , then by consuming the symbol a , you can go to state q1 . And the state diagram for δ(q0, a) → q1 :
(q0)
and transition table :
+----+----+ |Q\Σ | a | +----+----+ | q0 | q1 | +----+----+
and everything determines the map (q0, a) to (q1) .
Some authors write δ ⊆ Q×Σ → Q in the formal definition of DFA, which means that δ is a partial function (not defined for the complete domain Q×Σ ). We can always determine δ in the full domain that was once needed, for example, to look for a DFA add-on. Here ( DFA Supplement ) I wrote two DFAs for the same language, one of which is a partial DFA and the other DFA add-on.