1. The plaintiffs' appeal is dismissed.

2. The costs of appeal, including the part arising from the supplementary participation, are assessed against the Plaintiffs.

1. The reasoning of the court of first instance’s explanation concerning the instant case is as follows, and the reasoning of the judgment of the court of first instance is the same as that of the judgment of the court of first instance, in addition to adding the judgment on the Plaintiffs’ assertion under Article 8(2) of the Administrative Litigation Act and the main sentence of Article 420 of the Civil Procedure Act.

(1) In addition, the court below's findings and determination that rejected the plaintiffs' claims are justifiable even if the first instance court and the evidence submitted by this court are examined as follows: 【The part to be used after dismissal ] the fourth instance court's "Enforcement Decree of the Act on the Maintenance and Improvement of Urban Areas and Dwelling Conditions for Residents (hereinafter "the Act on the Maintenance and Improvement of Urban Areas and Dwelling Conditions for Residents")" and the "Enforcement Decree of the Act on the Maintenance and Improvement of Urban Areas and Dwelling Conditions for Residents (amended by Presidential Decree No. 28628, Feb. 9, 2018; hereinafter "Enforcement Decree of the Act on the Maintenance and Improvement of Urban Areas and Dwelling Conditions for Residents (hereinafter "the Act on the Maintenance and Improvement of Urban Areas and Dwelling Conditions for Residents")" under Article 10 of the "Act on the Maintenance and Improvement of Urban Areas and Dwelling Conditions for Residents (wholly amended by Act No. 14567, Feb. 8, 2017; hereinafter "the Act on the Maintenance and Improvement of Urban Areas and Dwelling Conditions for Residents")."

2. Judgment on the plaintiffs' assertion

A. Although the plaintiffs' alleged intervenor obtained written resolution and written consent for the establishment of an association from the union members, it is difficult to view that at least 15 of them agreed to establish an association solely because the body of the name portion among the members' personal information column has changed (e.g., as follows) and all of Chapter 416.