Abstract: Disclosed is a method and apparatus for matching regular expressions. A buffer of symbols giving a number of the last occurrence positions of each symbol is maintained. When two constants match on either side of a regular expression operator, the buffer of symbols is queried to determine if a member of the complement of the regular expression operator occurred between the two constants. If so, then the operator was not satisfied. If not, then the operator was satisfied.

Abstract: Disclosed is a method and apparatus for matching regular expressions. A buffer of symbols giving a number of the last occurrence positions of each symbol is maintained. When two constants match on either side of a regular expression operator, the buffer of symbols is queried to determine if a member of the complement of the regular expression operator occurred between the two constants. If so, then the operator was not satisfied. If not, then the operator was satisfied.

Abstract: Disclosed is a method and apparatus for matching regular expressions. A buffer of symbols giving a number of the last occurrence positions of each symbol is maintained. When two constants match on either side of a regular expression operator, the buffer of symbols is queried to determine if a member of the complement of the regular expression operator occurred between the two constants. If so, then the operator was not satisfied. If not, then the operator was satisfied.

Abstract: Disclosed is a method and apparatus for matching regular expressions. A buffer of symbols giving a number of the last occurrence positions of each symbol is maintained. When two constants match on either side of a regular expression operator, the buffer of symbols is queried to determine if a member of the complement of the regular expression operator occurred between the two constants. If so, then the operator was not satisfied. If not, then the operator was satisfied.

Abstract: The present invention is directed to a method and apparatus to find an optimal unification substitution for formulas in a technology library. In an exemplary aspect of the present invention, a method for finding an optimal unification substitution for formulas in a technology library during integrated circuit design may include the following steps: (a) receiving input including a list L of pairs of formulas in standard form, a set S of substitutions for variables, a right part e(x1, . . . , xp) of an identity, and an information I={t, h, r, a, p} on best application; (b) when the list L is not empty, extracting and removing first pair (f?(A?1, . . . , A?n?), g?(B?1, . . . , B?m?)) from the list L; (c) removing head inverters and buffers from formulas f?(A?1, . . . , A?n?) and g?(B?1, . . . , B?m?)) and obtaining a pair (f(A1, . . . , An), g(B1, . . . , Bm)); (d) when the ƒ is a commutative operation but neither a variable nor constant, and when heads of the formulas f(A1, . . . , An) and g(B1, . . .