Mark Krasnosel'skii was born on April 27, 1920.
Krasnoselskii fixed point theorem states that under certain sircumstances the operator has at least one fixed point in a subset of a Banach space. It doesn't say anything about uniqueness of solutions, just existence, but sometimes this is usefull enough, and perhaps you can get uniqueness by some other way. I hope this answers your question
Mark Beeson was born in 1962.
Mark Stephenson was born in 1976.
Mark Stemmler was born in 1960.
Oliver Mark was born in 1963.
Mark Chai was born in 1954.
Mark Gorenstein was born in 1946.
Mark was born in 1978.
Mark McLaughlin was born on 1975-12-02.
Mark Russell was born on August 23, 1932.
Mark Boyle was born on May 11, 1934.
Mark Connor was born in 1949.