Closing arguments are scheduled to begin today in what has been a bloody battle between soft drink giants.

Allegheny Pepsi-Cola Bottling Co. has charged that Coca-Cola conspired with one of the nation's largest investment banking firms, bankrolling a dummy corporation that would remain secretly in Coca-Cola's control, and that the newly created franchise sold its product below cost to drive the Pepsi bottler from the market.

At the heart of Allegheny's case are several memorandums between Coca-Cola executives, gained in pretrial discovery. The memorandums purportedly reveal a scheme between Coca-Cola and Citicorp Venture Capital avoiding Federal Trade Commission regulations to set up Coca-Cola's independent franchise, Mid-Atlantic Bottling Co. The memorandums are replete with phrases such as "off balance-sheet financing" and interim buyers called "parking lot attendants" who will "do what we say" and sell the business back to Coca-Cola on demand.

Coca-Cola has argued that no such deal ever occurred. The company merely wanted the first veto on potential buyers.

The trial's final witness, Donald R. Keough, president of the Coca-Cola Co., told the jury that Coca-Cola had legitimate business reasons for helping set up what has been portrayed as a sweetheart financing package for the Mid-Atlantic deal. Mid-Atlantic was created by combining the independent J. E. Crass Bottling Companies with the wholly-owned Coca-Cola Bottling Co. of Baltimore.

In his cross-examination, Allegheny attorney Harvey D. Myerson was unsuccessful in his attempt to ask Keough about documents allegedly containing references to the deal. Keough repeatedly denied knowledge of such documents, prompting Judge John A. MacKenzie to stop the questioning.

Myerson was able to offer into evidence, however, a memorandum to Keough from Lawrence R. Cowart, a senior vice president at Coca-Cola, that mentioned "this parking approach with Citicorp Venture Capital."

A certified public accountant retained by Allegheny had testified that a study of Mid-Atlantic's books showed the bottler sold below cost, on four package sizes, more than 70 percent of the time during a nine month period beginning October 1980. Allegheny has argued that such "predatory" pricing was possible because of a "deep pocket" of funds provided by Coca-Cola through syrup rebates and other monetary transfers.

Last Wednesday, a certified public accountant retained by Coca-Cola testified that the other side's expert erred in saying Mid-Atlantic sold at below cost for an extended period of time. Samuel A. Derieux of Richmond, an adviser to the Federal Accounting Standards Board, said that such pricing existed less than 3 percent of the time, and that the profit loss was because of the slack winter period in a seasonal business.

Derieux challenged testimony by two of Allegheny's experts, H. Leon Hodges, a Chesapeake certified public accountant and Bernard Norwood, a specialist in antitrust economics with Robert R. Nathan Associates, a Washington, D.C. consulting firm. Hodges had testified about below-cost pricing by Mid-Atlantic and Norwood had explained to the jury that, had Allegheny not been forced to compete with such "predatory" pricing, the Pepsi bottler would have made a profit of $20 million, 25 percent more than the $16 million it made in the first full year the two firms competed. Coca-Cola has argued Norwood's findings are based on projections from a period before the creation of Mid-Atlantic. Then, Crass was selling at high prices for quick profits that would appeal to the firm's potential buyers, and Allegheny was able to keep its prices up accordingly.

Allegheny's experts had failed to consider variable expenses, Derieux charged.

But on cross-examination by Allegheny attorney Bruce Topman, Derieux had difficulty explaining why certain figures he used did not jibe when transferred from his own analysis of Mid-Atlantic's pricing practices to his analysis of Hodge's findings.