added '@' for context, rewriting query X:sa as #BEG(X , sa), updated examples
diff --git a/examples/cosmas17.json b/examples/cosmas17.json
deleted file mode 100644
index 61333fd..0000000
--- a/examples/cosmas17.json
+++ /dev/null
@@ -1,31 +0,0 @@
-{
-  "context" : "http://ids-mannheim.de/ns/KorAP/json-ld/v0.1/context.jsonld",
-  "query" : {
-    "@type" : "korap:group",
-    "operation" : "operation:submatch",
-    "classRef" : [ 1 ],
-    "operands" : [ {
-      "@type" : "korap:group",
-      "operation" : "operation:position",
-      "frame" : "frame:startswith",
-      "operands" : [ {
-        "@type" : "korap:span",
-        "key" : "s"
-      }, {
-        "@type" : "korap:group",
-        "operation" : "operation:class",
-        "class" : 1,
-        "operands" : [ {
-          "@type" : "korap:token",
-          "wrap" : {
-            "@type" : "korap:term",
-            "caseInsensitive" : true,
-            "key" : "wegen",
-            "layer" : "orth",
-            "match" : "match:eq"
-          }
-        } ]
-      } ]
-    } ]
-  }
-}
\ No newline at end of file
diff --git a/examples/cosmas1.json b/examples/cosmas2_1.json
similarity index 69%
rename from examples/cosmas1.json
rename to examples/cosmas2_1.json
index 871fce1..42cf066 100644
--- a/examples/cosmas1.json
+++ b/examples/cosmas2_1.json
@@ -1,5 +1,5 @@
 {
-  "context" : "http://ids-mannheim.de/ns/KorAP/json-ld/v0.1/context.jsonld",
+  "@context" : "http://ids-mannheim.de/ns/KorAP/json-ld/v0.1/context.jsonld",
   "query" : {
     "@type" : "korap:token",
     "wrap" : {
diff --git a/examples/cosmas10.json b/examples/cosmas2_10.json
similarity index 91%
rename from examples/cosmas10.json
rename to examples/cosmas2_10.json
index d958810..ae4dd0a 100644
--- a/examples/cosmas10.json
+++ b/examples/cosmas2_10.json
@@ -1,5 +1,5 @@
 {
-  "context" : "http://ids-mannheim.de/ns/KorAP/json-ld/v0.1/context.jsonld",
+  "@context" : "http://ids-mannheim.de/ns/KorAP/json-ld/v0.1/context.jsonld",
   "query" : {
     "@type" : "korap:group",
     "operation" : "operation:sequence",
diff --git a/examples/cosmas11.json b/examples/cosmas2_11.json
similarity index 91%
rename from examples/cosmas11.json
rename to examples/cosmas2_11.json
index 6cd164f..43d37d1 100644
--- a/examples/cosmas11.json
+++ b/examples/cosmas2_11.json
@@ -1,5 +1,5 @@
 {
-  "context" : "http://ids-mannheim.de/ns/KorAP/json-ld/v0.1/context.jsonld",
+  "@context" : "http://ids-mannheim.de/ns/KorAP/json-ld/v0.1/context.jsonld",
   "query" : {
     "@type" : "korap:group",
     "operation" : "operation:sequence",
diff --git a/examples/cosmas12.json b/examples/cosmas2_12.json
similarity index 91%
rename from examples/cosmas12.json
rename to examples/cosmas2_12.json
index e6d8895..4031774 100644
--- a/examples/cosmas12.json
+++ b/examples/cosmas2_12.json
@@ -1,5 +1,5 @@
 {
-  "context" : "http://ids-mannheim.de/ns/KorAP/json-ld/v0.1/context.jsonld",
+  "@context" : "http://ids-mannheim.de/ns/KorAP/json-ld/v0.1/context.jsonld",
   "query" : {
     "@type" : "korap:group",
     "operation" : "operation:sequence",
diff --git a/examples/cosmas13.json b/examples/cosmas2_13.json
similarity index 93%
rename from examples/cosmas13.json
rename to examples/cosmas2_13.json
index ea83cba..52bf24a 100644
--- a/examples/cosmas13.json
+++ b/examples/cosmas2_13.json
@@ -1,5 +1,5 @@
 {
-  "context" : "http://ids-mannheim.de/ns/KorAP/json-ld/v0.1/context.jsonld",
+  "@context" : "http://ids-mannheim.de/ns/KorAP/json-ld/v0.1/context.jsonld",
   "query" : {
     "@type" : "korap:group",
     "operation" : "operation:sequence",
diff --git a/examples/cosmas14.json b/examples/cosmas2_14.json
similarity index 91%
rename from examples/cosmas14.json
rename to examples/cosmas2_14.json
index f7fd874..bb80964 100644
--- a/examples/cosmas14.json
+++ b/examples/cosmas2_14.json
@@ -1,5 +1,5 @@
 {
-  "context" : "http://ids-mannheim.de/ns/KorAP/json-ld/v0.1/context.jsonld",
+  "@context" : "http://ids-mannheim.de/ns/KorAP/json-ld/v0.1/context.jsonld",
   "query" : {
     "@type" : "korap:group",
     "operation" : "operation:sequence",
diff --git a/examples/cosmas15.json b/examples/cosmas2_15.json
similarity index 89%
rename from examples/cosmas15.json
rename to examples/cosmas2_15.json
index f5aabc0..1980eba 100644
--- a/examples/cosmas15.json
+++ b/examples/cosmas2_15.json
@@ -1,5 +1,5 @@
 {
-  "context" : "http://ids-mannheim.de/ns/KorAP/json-ld/v0.1/context.jsonld",
+  "@context" : "http://ids-mannheim.de/ns/KorAP/json-ld/v0.1/context.jsonld",
   "query" : {
     "@type" : "korap:group",
     "operation" : "operation:submatch",
diff --git a/examples/cosmas16.json b/examples/cosmas2_16.json
similarity index 89%
rename from examples/cosmas16.json
rename to examples/cosmas2_16.json
index 61333fd..15303f4 100644
--- a/examples/cosmas16.json
+++ b/examples/cosmas2_16.json
@@ -1,5 +1,5 @@
 {
-  "context" : "http://ids-mannheim.de/ns/KorAP/json-ld/v0.1/context.jsonld",
+  "@context" : "http://ids-mannheim.de/ns/KorAP/json-ld/v0.1/context.jsonld",
   "query" : {
     "@type" : "korap:group",
     "operation" : "operation:submatch",
diff --git a/examples/cosmas16.json b/examples/cosmas2_17.json
similarity index 89%
copy from examples/cosmas16.json
copy to examples/cosmas2_17.json
index 61333fd..15303f4 100644
--- a/examples/cosmas16.json
+++ b/examples/cosmas2_17.json
@@ -1,5 +1,5 @@
 {
-  "context" : "http://ids-mannheim.de/ns/KorAP/json-ld/v0.1/context.jsonld",
+  "@context" : "http://ids-mannheim.de/ns/KorAP/json-ld/v0.1/context.jsonld",
   "query" : {
     "@type" : "korap:group",
     "operation" : "operation:submatch",
diff --git a/examples/cosmas18.json b/examples/cosmas2_18.json
similarity index 71%
rename from examples/cosmas18.json
rename to examples/cosmas2_18.json
index c27404e..944a465 100644
--- a/examples/cosmas18.json
+++ b/examples/cosmas2_18.json
@@ -1,5 +1,5 @@
 {
-  "context" : "http://ids-mannheim.de/ns/KorAP/json-ld/v0.1/context.jsonld",
+  "@context" : "http://ids-mannheim.de/ns/KorAP/json-ld/v0.1/context.jsonld",
   "query" : {
     "@type" : "korap:group",
     "operation" : "operation:submatch",
diff --git a/examples/cosmas19.json b/examples/cosmas2_19.json
similarity index 89%
rename from examples/cosmas19.json
rename to examples/cosmas2_19.json
index b31d80b..3f8fc30 100644
--- a/examples/cosmas19.json
+++ b/examples/cosmas2_19.json
@@ -1,5 +1,5 @@
 {
-  "context" : "http://ids-mannheim.de/ns/KorAP/json-ld/v0.1/context.jsonld",
+  "@context" : "http://ids-mannheim.de/ns/KorAP/json-ld/v0.1/context.jsonld",
   "query" : {
     "@type" : "korap:group",
     "operation" : "operation:submatch",
diff --git a/examples/cosmas2.json b/examples/cosmas2_2.json
similarity index 85%
rename from examples/cosmas2.json
rename to examples/cosmas2_2.json
index fdcb2d3..b8d6267 100644
--- a/examples/cosmas2.json
+++ b/examples/cosmas2_2.json
@@ -1,5 +1,5 @@
 {
-  "context" : "http://ids-mannheim.de/ns/KorAP/json-ld/v0.1/context.jsonld",
+  "@context" : "http://ids-mannheim.de/ns/KorAP/json-ld/v0.1/context.jsonld",
   "query" : {
     "@type" : "korap:group",
     "operation" : "operation:sequence",
diff --git a/examples/cosmas20.json b/examples/cosmas2_20.json
similarity index 89%
rename from examples/cosmas20.json
rename to examples/cosmas2_20.json
index 32887c7..991689f 100644
--- a/examples/cosmas20.json
+++ b/examples/cosmas2_20.json
@@ -1,5 +1,5 @@
 {
-  "context" : "http://ids-mannheim.de/ns/KorAP/json-ld/v0.1/context.jsonld",
+  "@context" : "http://ids-mannheim.de/ns/KorAP/json-ld/v0.1/context.jsonld",
   "query" : {
     "@type" : "korap:group",
     "operation" : "operation:submatch",
diff --git a/examples/cosmas3.json b/examples/cosmas2_3.json
similarity index 88%
rename from examples/cosmas3.json
rename to examples/cosmas2_3.json
index 2c77f42..f43b829 100644
--- a/examples/cosmas3.json
+++ b/examples/cosmas2_3.json
@@ -1,5 +1,5 @@
 {
-  "context" : "http://ids-mannheim.de/ns/KorAP/json-ld/v0.1/context.jsonld",
+  "@context" : "http://ids-mannheim.de/ns/KorAP/json-ld/v0.1/context.jsonld",
   "query" : {
     "@type" : "korap:group",
     "operation" : "operation:sequence",
diff --git a/examples/cosmas4.json b/examples/cosmas2_4.json
similarity index 89%
rename from examples/cosmas4.json
rename to examples/cosmas2_4.json
index 55eab65..9e010c5 100644
--- a/examples/cosmas4.json
+++ b/examples/cosmas2_4.json
@@ -1,5 +1,5 @@
 {
-  "context" : "http://ids-mannheim.de/ns/KorAP/json-ld/v0.1/context.jsonld",
+  "@context" : "http://ids-mannheim.de/ns/KorAP/json-ld/v0.1/context.jsonld",
   "query" : {
     "@type" : "korap:group",
     "operation" : "operation:sequence",
diff --git a/examples/cosmas5.json b/examples/cosmas2_5.json
similarity index 93%
copy from examples/cosmas5.json
copy to examples/cosmas2_5.json
index ec1cdbf..a96845d 100644
--- a/examples/cosmas5.json
+++ b/examples/cosmas2_5.json
@@ -1,5 +1,5 @@
 {
-  "context" : "http://ids-mannheim.de/ns/KorAP/json-ld/v0.1/context.jsonld",
+  "@context" : "http://ids-mannheim.de/ns/KorAP/json-ld/v0.1/context.jsonld",
   "query" : {
     "@type" : "korap:group",
     "operation" : "operation:sequence",
diff --git a/examples/cosmas5.json b/examples/cosmas2_6.json
similarity index 93%
rename from examples/cosmas5.json
rename to examples/cosmas2_6.json
index ec1cdbf..06a9726 100644
--- a/examples/cosmas5.json
+++ b/examples/cosmas2_6.json
@@ -1,5 +1,5 @@
 {
-  "context" : "http://ids-mannheim.de/ns/KorAP/json-ld/v0.1/context.jsonld",
+  "@context" : "http://ids-mannheim.de/ns/KorAP/json-ld/v0.1/context.jsonld",
   "query" : {
     "@type" : "korap:group",
     "operation" : "operation:sequence",
@@ -11,6 +11,14 @@
       "max" : 5
     } ],
     "operands" : [ {
+      "@type" : "korap:token",
+      "wrap" : {
+        "@type" : "korap:term",
+        "key" : "Tisch",
+        "layer" : "orth",
+        "match" : "match:eq"
+      }
+    }, {
       "@type" : "korap:group",
       "operation" : "operation:sequence",
       "inOrder" : true,
@@ -42,14 +50,6 @@
           "match" : "match:eq"
         }
       } ]
-    }, {
-      "@type" : "korap:token",
-      "wrap" : {
-        "@type" : "korap:term",
-        "key" : "Tisch",
-        "layer" : "orth",
-        "match" : "match:eq"
-      }
     } ]
   }
 }
\ No newline at end of file
diff --git a/examples/cosmas7.json b/examples/cosmas2_7.json
similarity index 95%
rename from examples/cosmas7.json
rename to examples/cosmas2_7.json
index 0bf2ba3..f4b8f2a 100644
--- a/examples/cosmas7.json
+++ b/examples/cosmas2_7.json
@@ -1,5 +1,5 @@
 {
-  "context" : "http://ids-mannheim.de/ns/KorAP/json-ld/v0.1/context.jsonld",
+  "@context" : "http://ids-mannheim.de/ns/KorAP/json-ld/v0.1/context.jsonld",
   "query" : {
     "@type" : "korap:group",
     "operation" : "operation:sequence",
diff --git a/examples/cosmas8.json b/examples/cosmas2_8.json
similarity index 91%
rename from examples/cosmas8.json
rename to examples/cosmas2_8.json
index a8f4a3f..c9d2f85 100644
--- a/examples/cosmas8.json
+++ b/examples/cosmas2_8.json
@@ -1,5 +1,5 @@
 {
-  "context" : "http://ids-mannheim.de/ns/KorAP/json-ld/v0.1/context.jsonld",
+  "@context" : "http://ids-mannheim.de/ns/KorAP/json-ld/v0.1/context.jsonld",
   "query" : {
     "@type" : "korap:group",
     "operation" : "operation:sequence",
diff --git a/examples/cosmas9.json b/examples/cosmas2_9.json
similarity index 91%
rename from examples/cosmas9.json
rename to examples/cosmas2_9.json
index 865226c..b42eefc 100644
--- a/examples/cosmas9.json
+++ b/examples/cosmas2_9.json
@@ -1,5 +1,5 @@
 {
-  "context" : "http://ids-mannheim.de/ns/KorAP/json-ld/v0.1/context.jsonld",
+  "@context" : "http://ids-mannheim.de/ns/KorAP/json-ld/v0.1/context.jsonld",
   "query" : {
     "@type" : "korap:group",
     "operation" : "operation:sequence",
diff --git a/examples/cosmas6.json b/examples/cosmas6.json
deleted file mode 100644
index d52d5c7..0000000
--- a/examples/cosmas6.json
+++ /dev/null
@@ -1,55 +0,0 @@
-{
-  "context" : "http://ids-mannheim.de/ns/KorAP/json-ld/v0.1/context.jsonld",
-  "query" : {
-    "@type" : "korap:group",
-    "operation" : "operation:sequence",
-    "inOrder" : true,
-    "distances" : [ {
-      "@type" : "korap:distance",
-      "key" : "w",
-      "min" : 0,
-      "max" : 5
-    } ],
-    "operands" : [ {
-      "@type" : "korap:token",
-      "wrap" : {
-        "@type" : "korap:term",
-        "key" : "Tisch",
-        "layer" : "orth",
-        "match" : "match:eq"
-      }
-    }, {
-      "@type" : "korap:group",
-      "operation" : "operation:sequence",
-      "inOrder" : true,
-      "distances" : [ {
-        "@type" : "korap:distance",
-        "key" : "w",
-        "min" : 1,
-        "max" : 3
-      }, {
-        "@type" : "korap:distance",
-        "key" : "s",
-        "min" : 0,
-        "max" : 1
-      } ],
-      "operands" : [ {
-        "@type" : "korap:token",
-        "wrap" : {
-          "@type" : "korap:term",
-          "key" : "das",
-          "layer" : "orth",
-          "match" : "match:eq"
-        }
-      }, {
-        "@type" : "korap:token",
-        "wrap" : {
-          "@type" : "korap:term",
-          "key" : "Buch",
-          "layer" : "orth",
-          "match" : "match:eq"
-        }
-      } ]
-    } ]
-  }
-}
\ No newline at end of file