To call theatre 'postdramatic' involves subjecting the traditional relationship of theatre to drama to deconstruction and takes account of the numerous ways in which this relationship has been refigured in contemporary practice since the 1970s.

1.  本句宾语的主要结构是：subjecting...to deconstruction  将传统关系进行解构。

2.  A 和 B 之间的关系，正常的表达是：

relationship between A and B

不规范的表达为：

relationship of A and B

relationship of A to B （本句就是用了这种结构）

其他例句：

What's the relationship of the nations to Israel?
这些国家和以色列有什么关系？
The relationship of atrophic gastritis to cancer has been debated.
萎缩性胃炎与癌症的关系一直存在争议。