For reading attribute values from the Parent Element you can use the below syntax:
Thanks for your reply, this works for reading the parent attribute.
But How to write from an child-element analyses to the parent-element-attribute?
I cannot map this attribute from the analyses...
With Current versions , you cannot map an attribute from Parent Element as an output for your analysis at child element.
As a workaround you could use below 2 options.
1) Create an attribute in your child element and use this as an output for analysis and the in the Parent Element reference this attribute like '.\ChildElementName|ChildAttribute
2) Create the analysis at your parent level and reference inputs from child Element ( eg '.\ChildElementName|ChildAttribute') and map the output at parent Level itself.