fixed relation label separator

pom.xml

@@ -32,7 +32,7 @@
         <connection>scm:git:gitea@code-repo.d4science.org:D-Net/dhp-schemas.git</connection>
         <developerConnection>scm:git:gitea@code-repo.d4science.org:D-Net/dhp-schemas.git</developerConnection>
         <url>https://code-repo.d4science.org/D-Net/dhp-schemas/</url>
-        <tag>dhp-schemas-2.9.23</tag>
+        <tag>dhp-schemas-2.9.24</tag>
     </scm>
 
     <description>This module contains common schema classes meant to be used across the dnet-hadoop submodules</description>

src/main/java/eu/dnetlib/dhp/schema/common/ModelSupport.java

@@ -181,7 +181,7 @@ public class ModelSupport {
 	 * @return
 	 */
 	public static String rel(String relType, String subRelType, String relClass) {
-		return String.format("%s-%s-%s", relType, subRelType, relClass);
+		return String.format("%s_%s_%s", relType, subRelType, relClass);
 	}
 
 	private static final String schemeTemplate = "dnet:%s_%s_relations";