PHP framework to build Workflow Management system

I am looking for PHP framework to build a Workflow Management system.
While searching on net i got RADICORE which is quite best one. Just looking for more option so that I can compare them and go with one of them

My requirement is as:
I need framework that can define a workflow as we do in RADICORE and then play around it.
Playing means that if there 4 steps in my workflow, i can drop one and see How the workflow proceeds.
There are many frameworks through which you can generate a graph of your existing flow.
So i am basically interested in defining a workflow rather than generating the graph for existing framework.

And i should be an open source framework (basically PHP).

[Zeta/ezComponents has a Workflow engine.][1]. It's OpenSource and free to use. No clue how that compares to other engines though.


[1]:

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I can suggest [formapro/pvm](

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) library.

The library provides us with a frame to build a [workflow](

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) or business processes such as [BPMN](

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).
It works like this: you build a process, create nodes and transitions, link them up. Then you can do:

* Save process and execute later.
* Clone and execute several processes.
* Pause & continue execution.
* Supports async transition. Execute tasks in parallel.
* Supports fork-join, conditions, cycles and so on.

It is backed up by [workflow nets (WF-nets)](

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) and [graphs](

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) theories. . Here's a good [post on how Petri Nets works](

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)

It's very powerful and at the same easy to use (thanks to Petri Nets theory).