diff --git a/src/common.js b/src/common.js
index edb15e9ee9..74f8ee0aa1 100644
--- a/src/common.js
+++ b/src/common.js
@@ -2551,6 +2551,9 @@
                 if (part instanceof DomainInversion.And) {
                     var part_inversion = part.inverse(symbol, context);
                     var evaluated = typeof part_inversion == 'boolean';
+                    if (!~part.variables.indexOf(symbol)) {
+                        continue;
+                    }
                     if (!evaluated) {
                         result.push(part_inversion);
                     } else if (part_inversion) {
@@ -2602,7 +2605,7 @@
                 if (part instanceof DomainInversion.And) {
                     var part_inversion = part.inverse(symbol, context);
                     var evaluated = typeof part_inversion == 'boolean';
-                    if (!~this.variables.indexOf(symbol)) {
+                    if (!~part.variables.indexOf(symbol)) {
                         if (evaluated && part_inversion) {
                             return true;
                         }
diff --git a/tests/sao.js b/tests/sao.js
index 67ce759f95..71cc2a9cf3 100644
--- a/tests/sao.js
+++ b/tests/sao.js
@@ -2290,7 +2290,8 @@
             'domain_inversion(' + JSON.stringify(domain) + ', \'z\', ' +
                 JSON.stringify(context) + ')');
         context = {x: 5, y: 5};
-        QUnit.strictEqual(domain_inversion(domain, 'z', context), false,
+        QUnit.ok(compare(domain_inversion(domain, 'z', context),
+                [['z', '=', 3]]),
             'domain_inversion(' + JSON.stringify(domain) + ', \'z\', ' +
                 JSON.stringify(context) + ')');
         context = {x: 5, y: 7};
@@ -2315,7 +2316,8 @@
             'domain_inversion(' + JSON.stringify(domain) + ', \'z\', ' +
                 JSON.stringify(context) + ')');
         context = {y: 5};
-        QUnit.strictEqual(domain_inversion(domain, 'z', context), false,
+        QUnit.ok(compare(domain_inversion(domain, 'z', context),
+                [['z', '=', 3]]),
             'domain_inversion(' + JSON.stringify(domain) + ', \'z\', ' +
                 JSON.stringify(context) + ')');
         context = {x: 4, y: 7};