Belief revision logic 

Here is everything that exists in our world (so far). 

patient(jane).
patient(edima). 
patient(mary). 
patient(john).

age(jane, 21). 
age(edima, 20).
age(mary, 82). 
age(john, 50).

sex(jane, female). 
sex(edima, female).
sex(mary, female). 
sex(john, male).

lifeStyle(jane, smoking). 
lifeStyle(edima, highStess). 

isExperiencing(jane, chestPain). 
isExperiencing(jane, shortnessOfBreath). 
isExperiencing(edima, lightHeadedness). 
isExperiencing(edima, chestDiscomfort). 
isExperiencing(john, lightHeadedness). 
isExperiencing(john, fatigue). 

testResult(jane, calciumLevel, 300). 
testResult(edima, bloodPressure, 120/80). 

%% Belief set of a doctor diagnosing for CAD

unhealthyLifeStyle(inactivity). 
unhealthyLifeStyle(unhealthyEating). 
unhealthyLifeStyle(heavySmoking). 
unhealthyLifeStyle(highStress). 

healthRisk(highCalciumLevel). 
healthRisk(highBloodPressure).
healthRisk(heartAttack).
healthRisk(arrhythmia). 

%% Logical conclusions

hasSymptom(Patient, heartAttack) :- isExperiencing(Patient, Sign), Sign = chestPain | chestDiscomfort | shortnessOfBreath. 
hasSymptom(Patient, arrhythmia) :- isExperiencing(Patient, Sign), Sign = fatigue | lightHeadedness. 

%% Future plan: include other tests for cholesterol & diabetes
test(Patient, highCalciumLevel) :- testResult(Patient, calciumLevel, Result) ^ Result > 300. 
test(Patient, highBloodPressure) :- testResult(Patient, bloodPressure, Result) ^ Result > 180/120. 

cadRiskFactor(Patient) :- age(Patient, Age) ^ Age > 50. 
cadRiskFactor(Patient) :- hasSymptom(Patient, Symptom) ^ healthRisk(Symptom).
cadRiskFactor(Patient) :- lifeStyle(Patient, LifeStyle) ^ unhealthyLifeStyle(LifeStyle). 
cadRiskFactor(Patient) :- test(Patient, Test) ^ healthRisk(Test).