World No.2 Lleyton Hewitt has accused his professional peers of long-standing malice , including an attempt last year to dupe him into refusing a drug test .
WORLD No. 2 Lleyton Hewitt has accused the Association of Tennis Professionals of malice , including an alleged attempt last year to dupe him into refusing a drug test .
an mathematical programming model where the objective function is a linear function of the variables, and the constraints are linear equations and/or linear inequalities in terms of the variables.