Answer:
In the story "The Elevator" I believe that "the fat lady" that kept appearing in the elevator was real. According to the text, when the fat lady first appeared, Martin could very well describe her, "She wore a threadbare green coat that ballooned around her; her ankles bulged above dirty sneakers... Her features seemed very small, squashed together by the loose fleshy mounds of her cheeks. She had no chin, only a great swollen mass of neck, barely contained by the collar of her coat. Her sparse red hair was pinned in the back by a plastic barrette. And her blue eyes, though tiny, were sharp and penetrating, boring into Martin's fаce." Second, in the story, Martin could surely feel her presence and describe her. Martin could feel her in the elevator when he had to squeeze himself against a corner to make room for her. "She was so big that she filled the cubicle; her coat brushed against him, and he had to squeeze into the corner to make room for her-there certainly wouldn't have been room for another passenger." When he got off the elevator, "He didn't care what she thought. He ran past her, outside into the fresh air, and then he ran almost all the way to school. He had never felt such relief in his life." On the second time she got on the elevator, the events that occurred could prove she was real -"But there she was, massively real. "Going up!" he said, his voice a humiliating squeak She nodded, her flesh quivering, and stepped on. The door slammed. He watched her pudgy hand move toward the buttons." When she suggested going to level 18, she might have done this unpurpose to find out where Martin lived, and, when Martin said "Going up!", the story describes her response as a nod.
In conclusion, The Fat Lady conclusively is real, because Martins senses about her are notably real.
Note:
I almost felt inclined to say she is Imaginary, but I couldn't find any evidence. I hope this helps!
<em>-kiniwih426</em>