双变量多项式 meaning in Chinese

bivariate polynomial

Finally , degree reduction of interval rational triangular b - b surfaces is discussed . the problem is also converted to degree reduction of bi - variable polynomials with upper bound . according to degenerating conditions of triangular b - b surfaces , an optimization model is constructed and optimal solutions under certain constrains are calculated
先将该问题转化为双变量多项式的限制上界的降阶问题，然后采用最优化方法，结合三角b - b曲面的退化条件，建立约束优化模型，求出约束意义下的最优解。