Ballet as a medium of expression often retreats into its limitations, emphasizing the standard movements to a point where the dance is no longer creative. This week at the Boston Summer Theatre dance breaks through its restricting elements, adopts a contemporary aspect, and reveals itself as an abstract language that can be continuously built upon and expanded for all to enjoy.

The company is led by the well-known stars Nora Kaye and John Kriza and consists of 14 dancers drawn from the corps of the Ballet Theatre. The program up to last night included Pas de Deesses, Pas de Deux from Coppelia, A Streetcar Named Desire, and Interplay. Selections scheduled for the rest of the week are Designs With Strings, The Combat, Pas de Deux from Swan Lake, and Fancy Free (choreographed by Jerome Robbins and set to music by Leonard Bernstein.)

The first half of the Monday-Wednesday program was not so impressive as the second, since it included two very traditional and flowery numbers. Pas des Deesses was choreographed by Robert Joffrey, a young and talented dance creator who in this instance failed to get his message across. The ballet could have been very funny, since Joffrey took the standard set-up of one male and three girls--starting off together, then each little ballerina getting her chance to dance alone with the man, and finally the latter liking his three girls so much that he keeps them all--and apparently meant to lampoon it. But somehow the number, danced by Lupe Serrano, Ruth Ann Koesum, Catherine Horn, and Scott Douglas, was just corny, and the saccharine music by John Field did not help.

The next number was the traditional Pas de Deux, this time from the third act of Coppelia. Intended to give the prima ballerina and danseur noble a chance to demonstrate their technical virtuosity, it succeeded only in showing that Miss Kaye and Kriza, though excellent dancers are not suited for such restraining numbers.

A Streetcar Named Desire, the program's piece de resistance, revealed the company's great aptitude for the modern ballet-dance. Miss Kaye, who is today's formost exponent of dramatic roles, danced the part of Blanche Du Bois with all the neurotic and confused passion that the role embodies. Kriza was an excellent Stanley, primitive and animal-like in his simple world. Christine Mayer danced the faithful Stella and Scott Douglas the confused, well-intending Mitch.

Interplay, the final number of the evening, was a charming and light work choreographed by the very able Jerome Robbins.

Despite the disadvantages of the small stage and the accompaniment by piano only, the Ballet Theatre stars gave a diverse and entertaining performance. If the program for the rest of the week is equally good, local theatregoers will still have an opportunity to see dance at its best