In our model of computation, mathematical processes proceed a computation by exchanging messages. Each process is a stack machine, which is called an OX stack machine. The following methods are possible to realize communications between mathematical processes.
In OpenXM communication means exchange of messages between processes. A message has the following structure:
| destination | origin | |
| extension | ox message_tag | message_body |
We call it an OX message (OpenXM message object). OX message is the top level message object. The OX messages are classified into three types: DATA, COMMAND, and SPECIAL. They are distinguished by ox message_tag. The name of an ox message tag begins with OX_. Typical OX message tags are OX_COMMAND followed by SMobject and OX_DATA followed by CMObject. Each message object also has its tag. For SMobject, the name of a tag begins with SM_. For CMObject, the name of a tag begins with CMO_. An SMobject represents a stack machine command and categorized into several groups such as SMobject/Primitive, SMobject/Basic. The details of SMobjects will be explained in Section 5. We have already explained the Primitive CMObjects. We will describe the Basic CMObjects in Section 10.