A UNIVERSITY professor ''who fell from the very top of his profession'' to a state of chronic depression after cheating a teaching assistant of $10,800, was yesterday sentenced to four months in prison suspended for one year. The former head of the department of mathematics at the Chinese University of Hongkong, Chan Wai-leung, 52, pleaded guilty before Sha Tin Court to two counts of obtaining property by deception from Ms Pang Lan-fong by falsely representing that the money would be given to a postgraduate student from China who would share her workload. Senior Crown Counsel Mr Michael Holmes offered no evidence on a third charge which Chan denied. Defence counsel Mr Gary Alderdice, QC, told the court that since his arrest in May last year, Chan had lost his job and was now earning $15,000 a month as a clerk. Psychiatric reports showed he had been reduced to a state of chronic depression, he said. ''He has fallen from the very top of his profession for $10,000. ''It may have initially been his intention to use it for the benefit of other students, but that was not done.'' The court heard that in November 1991, Chan told Ms Pang one of the subjects he had previously given her to teach would be assigned to a student from China and so she would have to give half her monthly salary of $7,990 to the student through Chan. The court heard the exchange scheme set up in the 1980s with China had been largely the work of Chan. Mr Alderdice described Chan as ''an astonishing man of enormous academic ability and humanity''. Referring to reports handed to the court from Chan's colleagues and students, Mr Alderdice said: ''I have never seen testimonials in such glowing terms.'' He also handed in a compensation cheque from Chan payable to the Hongkong Government. Urging the magistrate to impose only a fine, he said a suspended sentence was unnecessary. ''It is most unlikely he will offend again. He has never offended before,'' he said. Magistrate Mr Michael Jenkins said: ''The worrying aspect of this case is the fact that the defendant has abused his position. ''What the defendant did I can only describe as inexplicable, bearing in mind the relatively small sums of money which would have had more significance to the victim. ''There is no doubt that the defendant is held in the highest esteem by his former colleagues and others. It is also clear that he shows full remorse for his acts.'' However, he said he did not consider simply imposing a fine would be a sufficient penalty. On each of the two charges to which Chan pleaded guilty he sentenced him to four months to run concurrently and suspended for one year. He made an order for compensation to be paid through the court to the victim.