As the process P(E), the AATT (indicated by the symbol 413) linked from the A of the $ block 412 is registered as a new T of an A$ block 421 and an AAT that is a destination of a link from the new T. After the registration, the A of the $ block 412, the AATT (indicated by the symbol 413) which is the destination of the link from the A, and the link are deleted.
As the process P(E), the ATAA (indicated by the symbol 414) linked from the T of the $ block 412 is registered as a new A of a T$ block 422 and an ATA that is a destination of a link from the new A. After the registration, the T of the $ block 412 is kept as it is, and the ATAA (indicated by the symbol 414) which is the destination of the link from the T, and the link are deleted.
As the process P(E), the TATA (indicated by the symbol 415) linked from the T of the $ block 412 is registered as a new A of the T$ block 422 and a TAT that is a destination of a link from the new A. After the registration, the T of the $ block 412 is kept as it is, and the TATA (indicated by the symbol 415) which is the destination of the link from the T, and the link are deleted. Thus, the $ block 412 becomes a $ block 481.
The following example is described with reference to the process P(w) shown in