THE CRIMINAL JUSTICE SYSTEM CONSISTS OF SEQUENCES OF RATHER TIGHTLY CONTROLLED ACTIVITIES. IT CAN BE UNDERSTOOD IN TERMS OF A PROCESS FLOW DIAGRAM AND IN THIS REGARD IT RESEMBLES MANY OTHER SYSTEMS WITH ORIGINS IN THE PHYSICAL SCIENCES. UNLIKE THE LATTER SYSTEMS, HOWEVER, THE CRIMINAL JUSTICE SYSTEM DOES NOT HAVE ITS INDIVIDUAL FUNCTIONS UNDERSTOOD IN TERMS OF WELL-DEFINED AND WELL-VERIFIED PHYSICAL LAWS. HOWEVER, BECAUSE ENGINEERS AND LAWYERS OFTEN DIVIDE ALL AVAILABLE INFORMATION ACCORDING TO ITS RELEVANT IMPORTANCE, CERTAIN NATURAL EQUIVALENCES ARISE IN CRIMINAL JUSTICE SYSTEMS, WHICH PERMIT DIRECT CONTACT WITH THE SET-THEORETICAL FOUNDATIONS OF MODERN ALGEBRA. THE EQUIVALENCES AND DATA RESOLUTIONS INDUCED BY AN AGREEMENT BETWEEN LAWYER AND ENGINEER TO USE A CERTAIN PROCESS FLOW DIAGRAM AND BY QUESTIONS POSED BY THE LAWYER WITHIN THE CONTEXT OF THIS AGREEMENT, ARE STRESSED. AN ALGEBRAIC SCHEME FOR MEDIATING THE DEMANDS POSED BY THESE TWO TYPES OF EQUIVALENCES IS INTRODUCED AND AS SHOWN, A DISPLAY SCHEME CAN BE COMPATIBLE WITH THE ALGEBRAIC ONE. SPECIFIC COURT MODELS, BASED ON THE JURISDICTIONS OF MARION AND ST. JOSEPH COUNTIES, INDIANA, ARE DISCUSSED. THE QUOTIENTS NECESSARY TO THE APPLICATION OF THE EQUIVALENCE CONCEPT ARE INTRODUCED, AND THE RESULTING DIAGRAMS AND DATA INTERROGATION ARE EXAMINED, AS ARE MEDIATIVE QUOTIENTS. A PRACTICAL METHOD FOR DATA DISPLAY IS ALSO REVIEWED. BASIC ACTIONS DIAGRAMS, DETAILED FLOW CHARTS, AND A FLOW-CHART LEGEND ARE PROVIDED. MODEL EQUATIONS AND RELATIVE GRAPHIC DISPLAYS ARE INCLUDED. AN APPENDIX CONTAINING A GLOSSARY OF FREQUENTLY USED LEGAL TERMS AND A LIST OF SELECTED REFERENCES ARE PROVIDED. (KBL)