In recent weeks, we have discussed problems that arise when people lose theater tickets.

A believable story usually persuades the management to seat ticketless patrons, and all is well. Usually.

But occasionally, as the house lights dim and the curtain is about to go up, other claimants for the seats arrive - with tickets in their hands. A decision must be made, and at once: Who gets the seats?

The tickets could have been lost, or stolen, perhaps from the mails. The thief or finder might have taken them to the box office for refund, and thereafter the tickets could have been resold to perfectly innocent buyers.

Are the people with the persuasive story con artists? Are the people with the tickets thieves? Or are both telling the truth? One can seldom be sure.

Al Barkan found some theater tickets on the sidewalk recently. There was no envelope; just four $18 tickets to a show at the Kennedy Center.

Al is no fool. He realized that if he were to announce that he had found $72 worth of tickets, he might hear from dozens of claimants. So he proceeded with caution.

He called the Kennedy Center and said, "I have found some tickets to one of your shows. I'll give you my name and phone number so that if somebody tells you he lost his tickets you can refer him to me. If he can tell me the date on the tickets and the face value, he can have them."

"We'll have somebody call you," was the answer. The next day, a woman who said she worked in the ticket office phoned, and Al went through the whole story again.

There was no need to use Al's procedure, the woman said. If he would just tell her the dates and locations specified on the tickets, she would probably be able to locate the owner and notify him that his tickets had been found.

Al was reluctant to do it her way, but finally agreed. After he identified the tickets, he asked, "If you can't trace the owner and nobody claims the tickets, do they revert to me?"

"On, on," she said quickly. "Those tickets are invalid now. They can be used only by the original purchaser."

Clang! Bells rang in Al's memory as he recalled my columns about missing tickets. "Who am I sepaking to?" he asked. "What is your name?" Al says the caller declined to identify herself, saying, "I don't have to give you my name."

That tore it. Al was angry, and called me. It made me angry to hear how he had been treated, and I called Leo Sullivan at the Kennedy Center. Leo was dismayed, but he's a gentle soul who doesn't waste time on anger. He's too busy setting things right.

"She shouldn't have given him such an answer," Leo said with a sigh. "I will talk to Chuck Bright, our director of sales, and see what we can find out. Tickets bought for cash are hard to trace, but we do have records on those bought by subscription, by mail order, or by Instant Charge. Let me go to work on it."

The next day, Leo called Al and told him the owner had been identified and had been given Al's name and number. "He'll call you direct and you can question him yourself."

The day after that, Leo received a call from Van Lung, owner of the Yenching Palace restaurant at Connecticut and Porter. It didn't take long for Al to realize that Lung was indeed the man who had paid $72 for four tickets to the Aug. 4 performance of the London Festival Ballet.

"Where did you find the tickets?" Lung asked.

"About a block from your restaurant," Al told him, "on the sidewalk in front of the Uptown Theatre - next to the post office."

"How strange," said Lung. "I lost them before I received them. They were never delivered to me."

By coincidence, Lung owns two Yenching Palaces, one on Connecticut Avenue and the other in Alexandria; and although Al owns only one place, it has not far from Lung's Alexandria restaurant.

So it was easy for Al to return Lung's tickets, and for Lung to insist that Al and his wife must have dinner with him some evening. And Leo insists that Al and his wife must come see a show as the Ken Cen's guests.

So almost everything has ended well. There is only one loose end. How did four tickets from the post office at 3430 Connecticut Ave. NW end up (without their envelope) on the sidewalk in front of 3426 Connecticut when they were supposed to be heading the other way, to 3524 Connecticut?

You'll have to figure out the answer for yourself. I'm stumped.