00309nam a2200121Ia 4500082001700000100002200017245003800039260004200077300002900119500002900148500000500177700000500182  a512bH636.TS  aHiggins, Peter M.  aTechniques of semigroups theoryb  aOxfordbOxford University Pressc1992  ax, 258p. Index. Glossary  a"Oxford science publns."  a  a