13th International Conference on Membrane Computing - MTA Sztaki

The efficiency of tissue P systems with cell separation relies on the environment
3. M 0 , M 1 , . . . , M q are strings over Γ .
4. R is a nite set of rules of the following forms:
Communication rules: (i, u/v, j), for i, j ∈ {0, . . . , q}, i ≠ j, u, v ∈ Γ ∗ ,
|u| + |v| > 0;
Separation rules: [a] i → [Γ 0 ] i [Γ 1 ] i , where i ∈ {0, . . . , q}, a ∈ Γ and i ≠ i out .
5. i out ∈ {0, . . . , q}.
A tissue P system with communication rules, with cell separation and without
environment is a tissue P system with communication rules and with cell
separation such that the alphabet E of the environment is empty.
Denition 2. A recognizer tissue P system with communication rules, with cell
separation and without environment of degree q + 1 is a tuple
where:
Π = (Γ, Σ, Γ 0 , Γ 1 , M 0 , M 1 , . . . , M q , R, i in , i out )
(Γ, Γ 0 , Γ 1 , M 0 , M 1 , . . . , M q , R, i out ) is a tissue P system with communication
rules, with cell separation and without environment of degree q + 1, as
dened previously.
The working alphabet Γ has two distinguished objects yes and no, at least
one copy of them present in some initial multisets M 0 , M 1 , . . . , M q .
Σ is an (input) alphabet strictly contained in Γ .
M 0 , M 1 , . . . , M q are strings over Γ \ Σ.
i in ∈ {1, . . . , q} is the input cell.
i out = 0 is the output cell.
All computations halt.
If C is a computation of Π, then either object yes or object no (but not
both) must have been released into cell 0, and only at the last step of the
computation.
For each w ∈ Σ ∗ , the computation of the system Π with input w ∈ Σ ∗ starts
from the conguration of the form (M 0 , M 1 , . . . , M iin + w, . . . , M q ; ∅), that is,
the input multiset w has been added to the contents of the input cell i in , and
we denote it by Π + w. Therefore, we have an initial conguration associated
with each input multiset w (over the input alphabet Σ) in this kind of systems.
Given a recognizer tissue P system with cell separation, and a halting computation
C of Π, the result of C is dened as in the previous section.
We denote by ̂TSC the class of recognizer tissue P systems with cell communication,
cell separation and without environment. For each natural number
k ≥ 1, we denote by ̂TSC(k) the class of recognizer tissue P systems with cell
separation, without environment, and with communication rules of length at
most k.
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