diff --git a/eo-parser/src/main/resources/XMIR.xsd b/eo-parser/src/main/resources/XMIR.xsd
index aa8d1b4dcc..cf80b14f1e 100644
--- a/eo-parser/src/main/resources/XMIR.xsd
+++ b/eo-parser/src/main/resources/XMIR.xsd
@@ -86,17 +86,6 @@ SOFTWARE.
       <xs:pattern value="[0-9]+|@|[a-z]\S*"/>
     </xs:restriction>
   </xs:simpleType>
-  <xs:simpleType name="function-name">
-    <xs:annotation>
-      <xs:appinfo>A name of function in the atom</xs:appinfo>
-      <xs:documentation>
-        The name of a function in the atom, which is used to reference the function from other objects or from the global scope.
-      </xs:documentation>
-    </xs:annotation>
-    <xs:restriction base="xs:string">
-      <xs:pattern value="[A-Z]\S*"/>
-    </xs:restriction>
-  </xs:simpleType>
   <xs:simpleType name="fqn">
     <xs:annotation>
       <xs:appinfo>A fully qualified name of an object</xs:appinfo>
@@ -182,7 +171,7 @@ SOFTWARE.
       </xs:annotation>
     </xs:attribute>
     <xs:attribute name="as" type="attribute-name"/>
-    <xs:attribute name="atom" type="function-name"/>
+    <xs:attribute name="atom" type="fqn"/>
     <xs:attribute name="loc" type="locator"/>
     <!--
     The following three are definitely temporary and should
diff --git a/eo-parser/src/test/java/org/eolang/parser/EoSyntaxTest.java b/eo-parser/src/test/java/org/eolang/parser/EoSyntaxTest.java
index fae75c468a..0af57b762b 100644
--- a/eo-parser/src/test/java/org/eolang/parser/EoSyntaxTest.java
+++ b/eo-parser/src/test/java/org/eolang/parser/EoSyntaxTest.java
@@ -29,9 +29,11 @@
 import com.jcabi.xml.XMLDocument;
 import java.io.IOException;
 import java.nio.charset.StandardCharsets;
-import java.util.Collection;
+import java.util.Set;
 import org.cactoos.io.InputOf;
 import org.cactoos.io.ResourceOf;
+import org.cactoos.iterable.Mapped;
+import org.cactoos.set.SetOf;
 import org.cactoos.text.TextOf;
 import org.eolang.jucs.ClasspathSource;
 import org.eolang.xax.XtSticky;
@@ -287,13 +289,18 @@ void checksXsdMistakes(final String yaml) throws Exception {
         );
         Assumptions.assumeTrue(story.map().get("skip") == null);
         final XML xml = story.after();
-        final Collection<SAXParseException> errors = xml.validate(
-            new XMLDocument(
-                new TextOf(new ResourceOf("XMIR.xsd")).asString()
+        final Set<String> errors = new SetOf<>(
+            new Mapped<>(
+                SAXParseException::toString,
+                xml.validate(
+                    new XMLDocument(
+                        new TextOf(new ResourceOf("XMIR.xsd")).asString()
+                    )
+                )
             )
         );
         MatcherAssert.assertThat(
-            Logger.format("correct number of errors found: %[list]s", errors),
+            Logger.format("correct number of errors found: %[list]s%n%s", errors, yaml),
             errors,
             Matchers.iterableWithSize(
                 Integer.parseInt(story.map().get("errors").toString())
diff --git a/eo-parser/src/test/resources/org/eolang/parser/xsd-mistakes/invalid-atom-name.yaml b/eo-parser/src/test/resources/org/eolang/parser/xsd-mistakes/invalid-atom-name.yaml
index 32de8a9b50..7ffcc5ecba 100644
--- a/eo-parser/src/test/resources/org/eolang/parser/xsd-mistakes/invalid-atom-name.yaml
+++ b/eo-parser/src/test/resources/org/eolang/parser/xsd-mistakes/invalid-atom-name.yaml
@@ -24,6 +24,6 @@ errors: 2
 document: |
   <program name='foo'>
     <objects>
-      <o name="foo" atom="wrong-function-name"/>
+      <o name="foo" atom="Wrong Object Name"/>
     </objects>
   </program>
diff --git a/eo-parser/src/test/resources/org/eolang/parser/xsd-mistakes/missing-program-title.yaml b/eo-parser/src/test/resources/org/eolang/parser/xsd-mistakes/missing-program-title.yaml
index c9e1eebfca..81ba105b6e 100644
--- a/eo-parser/src/test/resources/org/eolang/parser/xsd-mistakes/missing-program-title.yaml
+++ b/eo-parser/src/test/resources/org/eolang/parser/xsd-mistakes/missing-program-title.yaml
@@ -20,7 +20,7 @@
 # OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 # SOFTWARE.
 ---
-errors: 2
+errors: 1
 document: |
   <program>
     <objects/>