Ernest Tilden Parker is a professor emeritus from Ohio State University

Ohio State University

The Ohio State University, commonly referred to as Ohio State, is a public research university located in Columbus, Ohio. It was originally founded in 1870 as a land-grant university and is currently the third largest university campus in the United States...

. He is notable for his breakthrough work along with R. C. Bose and S. S. Shrikhande

S. S. Shrikhande

Sharadchandra Shankar Shrikhande is an Indian mathematician with distinguished and well-recognized achievements in combinatorial mathematics. He is notable for his breakthrough work along with R. C. Bose and E. T...

 in their disproof of the famous conjecture

Conjecture

A conjecture is a proposition that is unproven but is thought to be true and has not been disproven. Karl Popper pioneered the use of the term "conjecture" in scientific philosophy. Conjecture is contrasted by hypothesis , which is a testable statement based on accepted grounds...

 made by Leonhard Euler

Leonhard Euler

Leonhard Euler was a pioneering Swiss mathematician and physicist. He made important discoveries in fields as diverse as infinitesimal calculus and graph theory. He also introduced much of the modern mathematical terminology and notation, particularly for mathematical analysis, such as the notion...

 dated 1782 that there do not exist two mutually orthogonal latin square

Latin square

In combinatorics and in experimental design, a Latin square is an n × n array filled with n different symbols, each occurring exactly once in each row and exactly once in each column...

s of order 4n + 2 for every n. He is also well known (with K. B. Reid

K. B. Reid

Kenneth Brooks Reid, Jr. is a graph theorist and the founder faculty professor at California State University, San Marcos. He specializes in combinatorial mathematics. He is known for his work in tournaments, frequency partitions and aspects of voting theory. He is known on a disproof of a...

) on a disproof of a conjecture on tournaments by Erdős

Paul Erdos

Paul Erdős was a Hungarian mathematician. Erdős published more papers than any other mathematician in history, working with hundreds of collaborators. He worked on problems in combinatorics, graph theory, number theory, classical analysis, approximation theory, set theory, and probability theory...

 and Moser

Leo Moser

Leo Moser was an Austrian-Canadian mathematician, best known for his polygon notation....

.

Parker received his Ph.D. for his work 'On Quadruply Transitive Groups' submitted to Ohio State University in 1957; his advisor was Marshall Hall, Jr.

Marshall Hall (mathematician)

Marshall Hall, Jr. was an American mathematician who made contributions to group theory and combinatorics.- Career :...

.