common knowledge is the acquistion of fiqqa from important topics because because these topics are related from quran and the its accuracy is determined from quran and the sayings of holy prophet pbuhqiyaas,masaalh,marsala,aarf and hajjaj are related to it  are verified throughout (aam) is that word which is  used for many people words like muslimeen and nisaa  are used for it,there are two types of (aam) first type refers to that condition in which all the people are included and no one can be excluded from it and in this condition the word aam is dominant on its meaning.in this condition the saying is that it is compulsory on every one. the second condition is that aarf according to shariat is liable and it has two types first is aarfqooliaarfqooli is that which is transfered to people through practice and preaching the second type is aarffaali this type comes in that condition which is not against the majority. aarffassida is another type is that condition in which haram is concerted to halal and halal is converted to haram.