Disclosed is a composition comprising (A) at least one compound selected from the group consisting of an ether compound having two or more ether groups, a trivalent phosphorus compound, and a ketone compound, (B) a boron trihalide, and (C) an episulfide compound.

The method for setting polymerization conditions includes a physical property acquiring step, in which, when a composition which includes a polymerizable reactive compound including an episulfide compound, and a polymerization catalyst is heated and maintained at a predetermined temperature, a physical property value a derived from a functional group of the polymerizable reactive compound before heating and a physical property value b derived from a remaining functional group after maintaining heat for a predetermined time, are acquired; a remaining functional group ratio calculating step of calculating a remaining functional group ratio; a reaction rate coefficient calculating step for calculating a reaction rate coefficient; and a polymerization temperature calculating step of back-calculating each polymerization temperature every predetermined time in a polymerization time.

The method for setting polymerization conditions includes a physical property acquiring step, in which, when a composition which includes a polymerizable reactive compound including an episulfide compound, and a polymerization catalyst is heated and maintained at a predetermined temperature, a physical property value a derived from a functional group of the polymerizable reactive compound before heating and a physical property value b derived from a remaining functional group after maintaining heat for a predetermined time, are acquired; a remaining functional group ratio calculating step of calculating a remaining functional group ratio; a reaction rate coefficient calculating step for calculating a reaction rate coefficient; and a polymerization temperature calculating step of back-calculating each polymerization temperature every predetermined time in a polymerization time.

An encoding/decoding apparatus and method using a low-density parity-check code (LDPC code) is disclosed. Basic column group information, serving as a set of information regarding positions of rows with weight 1, is extracted from a reference column in each column group of a predetermined parity-check matrix. Column group information transforms the positions of rows with weight 1 into positions whose lengths are within a required parity length. A parity-check matrix is generated according to the generated column group information. Data is enclosed or decoded based on the generated parity-check matrix.

An encoding/decoding apparatus and method using a low-density parity-check code (LDPC code) is disclosed. Basic column group information, serving as a set of information regarding positions of rows with weight 1, is extracted from a reference column in each column group of a predetermined parity-check matrix. Column group information transforms the positions of rows with weight 1 into positions whose lengths are within a required parity length. A parity-check matrix is generated according to the generated column group information. Data is enclosed or decoded based on the generated parity-check matrix.

The method of producing an optical material of the present disclosure includes a step of mixing a resin monomer for an optical material and an additive to prepare a polymerizable composition for an optical material having a hue specified by L* of 70 or more b* of from −30 to 10 in the CIE 1976 (L*, a*, b*) color space when measured at a thickness of 10 mm, and a step of polymerizing and curing the polymerizable composition for an optical material.

A curable composition and an optical element including a cured product thereof. The curable composition includes an episulfide compound and an aromatic heterocyclic compound.

A curable composition and an optical element including a cured product thereof. The curable composition includes an episulfide compound and an aromatic heterocyclic compound.

Provided is a composition for optical materials that gives optical materials which can have at least one improved property selected from among satisfactory mold releasability after polymerization and curing, unsusceptibility to separation from the mold during polymerization and curing, transparency, and low-level striae. The present invention further provides a compound represented by formula (1). The composition for optical materials comprises the compound represented by formula (1) and a compound represented by formula (2). (In formula (1), X.sub.1 and X.sub.2 represent O or S, provided that both X.sub.1 and X.sub.2 are O or that X.sub.1 is O and X.sub.2 is S.)

##STR00001##

Provided is a composition for optical materials that gives optical materials which can have at least one improved property selected from among satisfactory mold releasability after polymerization and curing, unsusceptibility to separation from the mold during polymerization and curing, transparency, and low-level striae. The present invention further provides a compound represented by formula (1). The composition for optical materials comprises the compound represented by formula (1) and a compound represented by formula (2). (In formula (1), X.sub.1 and X.sub.2 represent O or S, provided that both X.sub.1 and X.sub.2 are O or that X.sub.1 is O and X.sub.2 is S.)

##STR00001##