13th International Conference on Membrane Computing - MTA Sztaki

A.E. Porreca, A. Leporati, G. Mauri, C. Zandron
0
0 0
0 0
0
0 b
w 00 a i
0
0
0
i 00
a
w 01 b i b w
i 01 0 0
0
⊔
i 10
w 10 ⊔ i ⊔ w
a 000 b 001 b 010 a 011 a 100
r 010,01
a w
Fig. 2. A possible conguration of the P system Π x (see Fig. 1) simulating the Turing
machine M after a few computation steps have been simulated. Here the current state
of M is r, the work tape contains the string ba, the input tape head is on cell 2 (binary
010), and the work tape head is on cell 1 (binary 01).
a 000
b 001
b 010
a 011
a 100
r 111
010,01
+
−
i 00
i 01
i 10
− 0
b
a
⊔
w 00
0
w 01 b i
0 0
w 10
0 0
a i
+
⊔ i
a w
0
b w
0
⊔ w
h
0
Fig. 3. Conguration of Π x (from Fig. 1) after the object b 010 (corresponding to the
symbol under the input tape head) has set the charge of membrane b i to positive,
allowing the state-object to identify it.
h
0 0
0
0 b
w 00
−
0
0 +
a
a i a w
+ 0
a 000 b 001 b 010 a 011 a 100
r ′′
010,01
w 10
⊔ i
⊔ w
h
⊔
w 01 b i
0 0
b w
0
i 00
i 01
i 10
Fig. 4. Conguration of Π x after the object a has set the charge of membrane a w to
positive, thus identifying the symbol under the work tape head.
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