Project Kaiser is a hierarchical project management software. It means that unlimited hierarchy of projects and tasks supported. Projects can have unlimited number of subprojects, and tasks can have unlimited number of subtasks. Both project and task may grow into a tree-like hierarchy.
In Project Kaiser term "Project" may have different meanings: complete company, department, office, or certain project in a company. It is displayed as a node in navigation tree. This node can have own team members, managers, workflows, etc. For example, here is an example of simple project structure "My Bakery", including two "Tasks" containers: "Production" and "Accounting":
In this example each department ("Production", "Accounting") has it's own list of tasks. You can see two levels in this hierarchy. For each node in this level we can specify own workgroup. Example workgroups:
Tom can see tasks from both Accountting and Production, while other team members - only tasks from their department. Example: Tom makes task in "Production" for John. John can execute task by himself, or re-assign it to other team member of "Production", or divide task into subtasks. Difference between roles "Manager" and "Executor" here is that "Executor" can not create new tasks, only excecute them.
More complicated company structure may look like this:
If certain team member added to "My Company", he has an access to tasks in any office, any department and any project. Team members of "Project A.2.1" have access to only tasks of "Project A.2.1".
Useful links: Getting Started (Documentation)
Hierarchical Task is a task which can be divided into subtasks. Each subtask can be also divided into subtasks, etc. Original task may grow into a complex hierarchy of subtasks with different assignee and responsible persons.
Another feature related to subtasks is "external" subtasks. Short example:
While working on "Task 1.1" for "Component 1" we found that "Component 2" must be extended with some functionality required by "Task 1.1". For that case we create "Task 2.1" and specify "Task 1.1" as a "supertask". Now when you look at the list of subtasks for "Task 1.1" you'll see "Task 2.1". This means "Task 2.1" is an external task for "Task 1.1" because it's created in different project component. Note that "Component 1" and "Component 2" may have different workgroups.
More information on subtasks and decomposition can be found in Users's Guide.