on invitation

基本解釋

KING: It's nice of you for coming here to hunt on invitation, we especially select a docility horse for you highness.
國王：很高興能見到邀請到你們來到這里狩獵，我們?yōu)橘F國白雪公主特意挑選了一批溫順的馬。
dolphinarea.spaces.live.com
On June 22, 2010, Chinese Foreign Minister Yang Jiechi had a phone conversation with UN Secretary-General Ban Ki-moon on invitation. The two sides exchanged views on the situation in Kyrgyzstan.
2010年6月22日，楊潔篪外長應約同聯(lián)合國秘書長潘基文通電話，雙方主要就吉爾吉斯斯坦局勢交換意見。
www.fmprc.gov.cn
In judicial practice, opinions of jurisprudential scholar, which provided by legal experts through participating in argumentation of cases on invitation of judicature.
司法實踐中，法學專家接受司法機關的邀請參與案件論證并出具專家意見，有利于案件的公正審理；

That could change on March 31, if Tehran accepts an invitation to join an international summit at The Hague.
But on his only mission to the region, earlier this month, he did not get an invitation to visit Pyongyang.
Israeli and Palestinian leaders have accepted an invitation from President Barack Obama for a three-way meeting Tuesday on the sidelines of the U.N.General Assembly in New York.

One interesting note, which may mean absolutely nothing: The artwork on the invitation closely resembles the drawings associated with its Google Now automated personal assistant on Android.
FORBES: New Phone? New Tablet? Google Sets Oct. 29 Android Event