Richard E. Ladner


Richard Emil Ladner is an American computer scientist known for his contributions to both theoretical computer science and assistive technology. Ladner is a professor emeritus at the University of Washington.

Richard E. Ladner
BornAugust 22, 1943
Berkeley, California
Alma materSt. Mary's College of California
University of California, Berkeley
Known forLadner's theorem
AwardsGuggenheim Fellowship
ACM Fellow
IEEE Fellow
SIGCHI Social Impact Award
SIGACCESS Outstanding Contribution to Computing and Accessibility Award
Scientific career
FieldsTheoretical Computer Science
Accessible computing
InstitutionsUniversity of Washington
ThesisMitotic recursively enumerable sets (1971)
Doctoral advisorRobert William Robinson


Richard Ladner was born as one of four children of deaf parents. Both of his parents were teachers at the California School for the Deaf when it was in Berkeley, California, and used American Sign Language and speech for communication. He grew up around deaf people and ASL but did not become fluent until he took some ASL classes in his early thirties.[1] Ladner earned his undergraduate degree from St. Mary's College of California in 1965, and his doctorate in mathematics from the University of California, Berkeley in 1971. Among other work, he obtained important results in the computational complexity theory[2] and in automata theory.[3] Since 1971, he has been a professor at the University of Washington.

In 1985, Ladner was awarded a Guggenheim Fellowship.[4] In 1995 Ladner was appointed an ACM Fellow,[5] and in 2009 an IEEE Fellow. He has served as an Area Editor for the Journal of the Association of Computing Machinery, Editor for SIAM Journal on Computing, an Associate Editor for the Journal of Computer and System Sciences, and Theory of Computing Systems. He is currently on the Editorial Boards for ACM Transactions on Accessible Computing and Communications of the ACM.


  1. ^ Ladner, Richard E. (1 September 2014). "My Path to Becoming an Accessibility Researcher". SIGACCESS Accessibility and Computing (110): 5–16. doi:10.1145/2670962.2670964. ISSN 1558-2337. S2CID 36904832. Retrieved 22 April 2017.
  2. ^ Ladner, Richard E. (1975). "On the Structure of Polynomial Time Reducibility". Journal of the ACM. 22 (1): 155–171. doi:10.1145/321864.321877. ISSN 0004-5411. S2CID 14352974.
  3. ^ Ladner, Richard E.; Lipton, Richard J.; Stockmeyer, Larry J. (1984). "Alternating Pushdown and Stack Automata". SIAM Journal on Computing. 13 (1): 135–155. doi:10.1137/0213010. ISSN 0097-5397.
  4. ^ "Richard E. Ladner". John Simon Guggenheim Memorial Foundation. Retrieved 2017-03-27.
  5. ^ "Richard E Ladner - Award Winner". Association for Computing Machinery. Retrieved 2017-03-26.

External linksEdit

  • Official website  
  • Richard E. Ladner at DBLP Bibliography Server  
  • Richard Emil Ladner at the Mathematics Genealogy Project  
  • My Path from to Becoming an Accessibility Researcher