diff --git a/.singularhistory b/.singularhistory
new file mode 100644
index 0000000..0e210ae
--- /dev/null
+++ b/.singularhistory
@@ -0,0 +1,14 @@
+ring r = 0,(x,y),ds;
+ideal f = x,xy+y6+y9;
+kbase(std(f));
+ring s = 0,(x,y),dp;
+ideal f = x,xy+y6+y9
+;
+kbase(std(f));
+ideal f = x,xy+y6+y8+y9;
+kbase(std(f));
+setring r;
+f = imap(s,f);
+f;
+kbase(std(f));
+quit;
diff --git a/comparison.md b/comparison.md
new file mode 100644
index 0000000..e69de29