According to T 234/86 (OJ 1989, 79), the opposition division can - and in certain circumstances must - maintain the patent as per the patentee's subordinate auxiliary request if he pursues main and auxiliary requests which are not allowable although taking precedence over the allowable one. Rejection of the requests which take precedence must be substantiated.
In T 5/89 (OJ 1992, 348) the board confirmed that a decision may confine itself to rejecting the main request only if all subordinate requests have been withdrawn. This principle was also confirmed in T 785/91 and T 81/93. Following T 5/89, the board in T 861/97 stated that deciding to revoke a patent solely on the basis of the main request when there was an expressly maintained auxiliary request constituted an infringement of Art. 113(2) EPC 1973.
In T 155/88 the board made it clear that the patentee could not be required to withdraw any request. If he filed one or more auxiliary requests in addition to a main request and did not withdraw any of them, an opposition division was obliged in its decision to give reasons why each successive request was either not admissible (in the exercise of its discretion under R. 57(1) EPC 1973 and R. 58(2) EPC 1973, see T 406/86, OJ 1989, 302), or not allowable on substantive grounds - see T 234/86, OJ 1989, 79. If an opposition division allowed an auxiliary request without giving reasons in its decision as to why the main request or preceding auxiliary requests were not allowable, such decision would be set aside as void and of no legal effect, and the appeal fee refunded on the basis of a substantial procedural violation, as was the case in T 234/86 and T 484/88.
The board in T 848/00 agreed with the reasoning of decision T 155/88 that if a patentee proposed amendments to its claims which arose out of the opposition and which were intended to meet the grounds of objection raised in the opposition by limiting the scope of protection sought, this should not normally be interpreted as an abandonment of the subject-matter protected by the claims of the patent as granted. But this statement did not influence how the amended set of claims was to be read because a restriction of claims was possible without abandoning the subject-matter of the patent specification as originally filed.