There are many similarities between AM and DMN.
Both support automatic or manual assertions(Human Decisions).
A connection in DMN is an Information Requirement and is shown as a decision dependency.
DMN includes an Authority Requirement from an Organizational Unit.
DMN is a formal notation and has executable logic.
AM does not prescribe how an automatic decision is calculated, that is left for implementation. DMN specifies this in more detail with business rules and FEEL expressions.
DMN has no construct that corresponds to a Perspective.
Assertum, the AM software, has minimal support for diagram notation. It has a stronger business focus, capturing business decisions that reflect governance, strategy, and capabilities as contributors to guiding business decisions.
The ability to move models between DMN and AM is very promising.