## 4 A World Wide Workflow  
An intermediate, incomplete solution to static workflows would be a dynamic workflow, open to everyone, scoped within some domain, and in the extreme, open to everyone on the Internet. The degree of scoping is determined by agreement upon semantics. We now sketch out what one possibility for this would look like as an expository device, rather than making a technical proposal. Given the agreed upon semantics, there could be a Process-XML (PXML) that would describe workflow tasks, as well as a protocol for exchanging PXML messages, along with process servers. Each task description would have a control section and a work description. The task description declares the previous task step in the workflow, the next step, and the performers of both. The prior step represents history and the next step represents the plan yet to be executed. The control part of the PXML would include standard workflow control constructs. These include to whom notifications should be sent if an assigned task has not been completed by certain times as well as forks and merges. The work section describes the input and output documents required for the task. Again, the input documents described are provided and are a part of the execution history. The output documents are planned and constitute the current criterion for task completion. \"Document\" in this context may be very abstract and even consist of a statement that the task has been completed. In addition, there may  
Figure 1: Workflow Modification. be pre-conditions and post-conditions associated with the task. The pre-conditions should have already been met when the task is assigned. The task actor should fulfill the post-conditions. Tasks are assigned to actors at first in the planned workflow, which may be incomplete. The workflow is monitored by a central server. Anyone within the domain of work, which might be the whole open Internet, may receive a task assignment. This might be the result of an open auction bidding on tasks, or from a search of capable actors. Upon receiving a task assignment, the actor may refuse or accept it. The actor may also change the workflow by modifying not only the output documents and post-conditions, but also the control part of the PXML describing the task. The only part that may not be changed is that part describing the execution history so far. Aside from this, since the PXML is an editable description, both work and control sections for planned work may be changed. Upon completing the task, the new PXML is sent to the next task assigner(s). However, before they receive it, the process server, which is mediating these communications, may object to changes because they violate certain policy constraints or because no viable workflow can be re-computed based upon the changes. The extent to which individual actors may also impose constraints, for instance making some inputs/outputs mandatory, requires further design analysis. Such an open workflow system could be available to anyone on the Internet. The requirements would be (1) agreed-upon message and task semantics, (2) client software able to receive, edit, and send task messages, (3) communicating with the central server (of which there may be multiple ones for multiple purposes). This software could be web-based, email-based, or app-based. The vision of \"flash companies\" described in [3] would be enabled and adequate semantics would likely quickly emerge for vertical markets as the need arose to better describe tasks, in auctions for example. The important point here is to see that the next step in workflow technology is dynamic workflows. And once one sees this, it is only a short step to making workflows obsolete entirely. The initial process template used for a open World Wide Workflow can be formulated by advanced technologies for composing services, since tasks and services will have much the same semantics. More important, some form of dynamic process synthesis and re-planning is needed to implement the workflow reformulation caused by task actor changes.