about normalised freq & lemmatisation

[xjzhou]

标准频数应怎样求得？公式是（单词频率/语料库容量）*100,000 还是乘以10，000？这个数值是不是不固定啊？when doing corpus studies, collocation for example, is it necessary to get this value?
what about lemmatisation? How to lemmatise a wordlist?