From EPC Standard
|Predecessors||Event, AND Operator|
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Possible succeeding element(s) is/are Event, Operator. Previous element(s) can be Event, AND Operator. The cardinalities are 1 (incoming) and 1 (outgoing) respectively .
The EPC syntax requires a function either to be preceded and followed by an operator or an event. Like events, functions may be linked to its predecessor and successor via a control flow arc. The control flow arc cannot connect two functions directly. , ,  A function may be attached with additional resources such as an organizational unit, data object or information system, which add further detail to the process element.
Functions are triggered by events. They are the active elements of an EPC that represent the activities of a modelled process and again raise events upon completion. The extended event driven process chain expands the semantic of functions, since they may be associated with the organizational unit performing the function or the data needed and created as output by the function. 
A function F is a part of an EPC = (E, F, P, C, l, A ), for which F is defined:
An element of F is called function. F ≠ ∅ F is a pairwise disjoint and finite set E ∩ F= ∅, F ∩ C= ∅ 1.
It is also called a node N, being part of N = E ∪ F ∪ P ∪ C.
Following requirements are made on functions so an EPC can be called relaxed syntactically correct:
- A function is connected to other nodes (•f and f•) by incoming and outgoing arcs.
- Functions have exactly one incoming and one outgoing arc: For each f ∈ F: |•f| = 1 ∧ |f•| = 1.
- A function neither starts nor ends an EPC.
- |F| ≥ 1. There is at least one function in an EPC.
- ∀f ∈ F : •f ⊆ (E ∪ CEF ) ∧ f• ⊆ (E ∪ CFE)
Functions must have events or ef-connectors in the preset and events or fe-connectors in the postset. That means a function always follows an event, which may be linked via connectors (except for end events)., 
To satisfy the requirements of pragmatic correctness every label of the model elements should follow a specified naming convention. A function represents the active and time consuming part of an EPC model, thereby a function’s name should reflect its characteristic as an activity and be created from a substantive and an active. The English naming convention suggestions for functions differ from the German conventions, as it is shown in the following table:
|English||Verb + Substantive(s)||"Processing order"|
|German||Substantive(s) + Verb||"Bestellung bearbeiten"|
The chosen name of a function should precisely describe, what is done at this specific part of the underlying process. To fulfill this requirement the naming process should be based heavily on the activities found in the process description.
<xs:complexType name="typeFunction"> <xs:sequence> <xs:element name="documentation" type="xs:anyType" minOccurs="0"/> <xs:element name="toolInfo" type="xs:anyType" minOccurs="0"/> <xs:element name="name" type="xs:string"/> <xs:element name="description" type="xs:string" minOccurs="0"/> <xs:choice minOccurs="0"> <xs:element name="graphics" type="epml:typeGraphics"/> </xs:choice> <xs:choice minOccurs="0"> <xs:element name="syntaxInfo"> <xs:complexType> <xs:attribute name="implicitType"> <xs:simpleType> <xs:restriction base="xs:string"> <xs:enumeration value="function"/> </xs:restriction> </xs:simpleType> </xs:attribute> </xs:complexType> </xs:element> </xs:choice> <xs:choice minOccurs="0"> <xs:element name="toProcess" type="epml:typeToProcess"/> </xs:choice> <xs:choice minOccurs="0" maxOccurs="unbounded"> <xs:element name="attribute" type="epml:typeAttribute"/> </xs:choice> </xs:sequence> <xs:attribute name="id" type="xs:positiveInteger" use="required"/> <xs:attribute name="defRef" type="xs:positiveInteger" use="optional"/> </xs:complexType>
-  ^ S. Appel, P. Kleber, S. Frischbier, T. Freudenreich, and A. Buchmann, “Modeling and execution of event stream processing in business processes,” Inf. Syst., vol. 46, pp. 140–156, 2014.
-  ^ J. Dehnert, J. Dehnert, P. Rittgen, and P. Rittgen, “Relaxed soundness of business processes,” Lect. notes Comput. Sci., pp. 157–170, 2001.
-  ^ 1 2 M. Fellmann, S. Bittmann, A. Karhof, C. Stolze, and O. Thomas, “Do We Need a Standard for EPC Modelling? The State of Syntactic, Semantic and Pragmatic Quality,” in 5th International Workshop on Enterprise Modelling and Information Systems Architectures (EMISA), 2013, pp. 103–116.
-  ^ F. Gottschalk, M. Rosemann, and W. M. P. van der Aalst, “My Own Process: Providing Dedicated Views on EPCs,” 4th GI Work. “EPC 2005 – Bus. Process Manag. with EPCs,” vol. 167, no. December, pp. 156–175, 2005.
-  ^ 1 2 A. W. Scheer, O. Thomas, and O. Adam, Process Modeling using Event-Driven Process Chains. 2005.
-  ^ J. Mendling, G. Neumann, and M. Nüttgens, “Yet another event-driven process chain,” in Lecture Notes in Computer Science, 2005, vol. 3649, p. 428.
-  ^ F. Gottschalk, W. M. P. van der Aalst, and M. H. Jansen-Vullers, “Merging Event-Driven Process Chains,” pp. 418–426, 2008.
-  ^ 1 2 O. Kopp, M. Wieland, and F. Leymann, “External and Internal Events in EPCs : e2EPCs,” 2nd Int. Work. event-driven Bus. Process Manag., pp. 381–392, 2010.
-  ^ A.-W. Scheer, M. Nüttgens, and V. Zimmermann, “Objektorientierte Ereignisgesteuerte Prozeßkette (oEPK): Methode und Anwendung,” Veröffentlichungen des Instituts für Wirtschaftsinformatik ( IWi ), Univ. des Saarlande, no. 141, 1997.
-  ^ B. List and B. Korherr, “A UML 2 Profile for Business Process Modelling *,” vol. 205, pp. 85–96, 2005.
-  ^ Mendling: Event Driven Process Chains - Metrics for Process Models, Volume 6 of the series Lecture Notes in Business Information Processing, pp. 17-57, 2009.
-  ^ M. Nüttgens, F. J. Rump "Syntax und Semantik Ereignisgesteuerter Prozessketten", Prozessorientierte Methoden und Werkzeuge für die Entwicklung von Informationssystemen - Promise 2002, P.69
-  ^ K. van Hee, O. Oanea, and N. Sidorova, "Colored Petri Nets to Verify Extended Event-Driven Process Chains", OTM Confederated International Conferences "On the Move to Meaningful Internet Systems", 2005, pp. 183-201.