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group, a tris(alkylcarbonyl)methylene group, and a tris (alkylsulfonyl)methylene group. Among those, the repeating unit ( c) is more preferably a repeating unit having a carboxyl group. As the repeating unit having an acidic group, all of a repeating unit where an acidic group is directly bonded to the main chain of the resin, such as repeating unit by an acrylic acid or a methacrylic acid, a repeating unit where an acidic group is bonded to the main chain of the resin through a linking group, and a repeating unit where an acidic group is introduced into the polymer chain terminal by using an acidic group-containing polymerization initiator or a chain transfer agent at the polymerization, are preferable. A repeat› ing unit by acrylic acid or methacrylic acid is particularly preferable. 

The acidic group which can be contained in the repeating unit ( c) may or may not contain an aromatic ring, but in a case where the aromatic ring is contained, it is preferably selected from acidic groups. In a case where the resin (A) contains the repeating unit having an acidic group, the content of the repeating unit having an acidic group in the resin (A) is usually 1 % by mole or more. 

Specific examples of the repeating unit having an acidic group are shown below, but the present invention is not limited thereto. 

In the specific examples, Rx represents H, CH$_{3}$ , CH$_{2}$OH, or CF$_{3}$ • 

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It is also preferable that the resin (A) further has repeating units below (hereinafter also referred to as "other repeating units") as repeating units other than the above repeating units. 

Examples of polymerizable monomers for forming other repeating units include styrene, alkyl-substituted styrene, alkoxy-substituted styrene, halogen-substituted styrene, O-alkylated styrene, O-acylated styrene, hydrogenated hydroxystyrene, maleic anhydride, acrylic acid derivatives (acrylic acid, acrylic ester, and the like), methacrylic acid derivatives (methacrylic acid, methacrylic ester, and the like), N-substituted maleimide, acrylonitrile, methacryloni› trile, vinyl naphthalene, vinyl anthracene, and indene, which may have a substituent. 

The resin (A) may or may not contain these other repeat› ing units, but in a case where these other repeating units are contained, the content of these other repeating units in the resin (A) is generally 1 % to 30% by mole, preferably 1 % to 20% by mole, and more preferably 5% to 10% by mole, with respect to all the repeating units constituting the resin (A). 

The resin (A) may contain a repeating unit represented by General Formula (IV) or General Formula (V). 

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In the formula, 

R$_{6 }$ represents a hydrogen atom, a hydroxy group, a linear, branched, or cyclic alkyl group having 1 to 10 carbon atoms, an alkoxy group or acyloxy group, a cyano group, a nitro group, an amino group, a halogen atom, an ester group (-OCOR or -COOR: R is an alkyl or fluorinated alkyl group having 1 to 6 carbon atoms), or a carboxyl group. 

n$_{3 }$ represents an integer of Oto 6. 

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-continued 

