---
title: Declarative Process Modelling
type: concept
tags: [bpm, declarative, constraint-based, flexibility, ltl, modelling-paradigm]
sources: ["[[sources/2008-pesic-declare-manual]]"]
created: 2026-04-15
updated: 2026-04-15
---

# Declarative Process Modelling

A modelling paradigm that specifies a process by **constraints on allowed behaviour** rather than an explicit control-flow graph. Any execution that does not violate the constraints is legal; the control-flow is implicit ([[sources/2008-pesic-declare-manual]], §1.1).

## Imperative vs declarative
| Dimension | Imperative (e.g. [[frameworks/bpmn]], Petri nets, YAWL) | Declarative (e.g. [[frameworks/declare]], ConDec, DecSerFlow) |
|---|---|---|
| Specification focus | HOW (ordered flow, gateways, begin/end) | WHAT (rules that must hold) |
| Default semantics | Only what is drawn is allowed | Everything not forbidden is allowed |
| Flexibility | Low — deviations = exceptions | High — broad permitted space |
| Best fit | Highly-structured, repetitive processes | Loosely-structured, knowledge-intensive, variable processes |
| Formal basis | Graph/token semantics | Temporal logic (LTL / LTLf / LDLf) |

## Why declarative
Imperative models over-specify flexible processes, forcing frequent deviations from the prescribed flow ([[sources/2008-pesic-declare-manual]], §1.1). Declarative models encode only the genuine regulatory, compliance, or causal constraints, leaving the rest of the behaviour space open to the participants.

## Formal grounding
- **Linear Temporal Logic (LTL)** — original DECLARE semantics.
- **LTL over finite traces (LTLf)** and **Linear Dynamic Logic on finite traces (LDLf)** — De Giacomo & Vardi, now standard for trace-finite process semantics.
- Constraints compile to **finite-state automata** for verification (satisfiability, dead activities, conflicts) and for run-time monitoring.

## Run-time constraint monitoring
Three-valued state commonly used (DECLARE traffic-light):
- **green** — satisfied.
- **orange** — temporarily violated, still repairable.
- **red** — permanently violated.

Constraint typing: mandatory · optional · conditional.

## Declarative process discovery
Automated mining of declarative models from event logs: Declare Miner (Maggi et al.), MINERful, DisCoveR. Contrast with imperative discovery (α-algorithm, Inductive Miner) — see [[methods/process-mining-basics]] and [[concepts/process-discovery]].

## Data-aware extensions
- **MP-Declare** / data-aware Declare — constraints conditioned on data predicates.
- **Declarative data-centric models** (e.g. DCDS, Montali) — integrate temporal constraints with persistent data.

## Related frameworks
- [[frameworks/declare]] — canonical implementation (ConDec, DecSerFlow).
- [[frameworks/cmmn]] — OMG case-management notation; shares declarative flavour but is GUI/marker-based rather than LTL-grounded.
- [[frameworks/dmn]] — declarative *decision* logic; complementary, not a control-flow competitor.

## Hub entities
[[entities/wil-van-der-aalst]] · [[entities/fabrizio-maggi]] · [[entities/marco-montali]] · Maja Pesic · Helen Schonenberg.