Table 1.

Rules for TLink expansion

Unary formals	Binary formals
If A→B, then B←A	If A→B and B→C, then A→C
If A←B, then B→A	If A→B and B↔C, then A→C
If A↔B, then B↔A	If A→B and A↔C, then C→B
	If A↔B and B↔C, then A↔C