Machine Learning-1 ：the definitions(maybe)

Two definitions of machine learning. Arthur Sarnuel described it as ：“the field of study that gives computer the ability to learn without being explicitly programmed.”This is an old ,informal definition.

Tom Mitchell provides a more modern definition：
“A computer program is said to learn from experience E with respected to some class of tasks T and performance measure P，if its performance at tasks in T，as measureed by P, improves with experience E”

for example：playing checkers

• E=the experience of playing many games of checkers
• T=the tasks of playing checkers
• P=the probability that the program will win the next game