[O1] ================================================ AMAST Links 02 01

	                     Helena Rasiowa

  Helena Rasiowa, descendant and member of the Polish School of Logic,
died on 9 August, 1994. Born on 20 June 1917, she begun the studies of
mathematics at the University of Warsaw in 1938. During the second
world war she continued the studies at the Underground University.
She wrote her Master's thesis under the supervision of Jan Lukasiewicz
and obtained her M.Sc. degree in 1945. She received her Ph.D. degree
under the supervision of Andrzej Mostowski in 1950. She held academic
positions at the University of Warsaw from 1945 till 1992. She served
as the Head of the Chair of Foundations of Mathematics (1964-1970) and
the Head of the Chair of Mathematical Logic (1970-1992).
  The study of the relationship between logic and algebra, originated
by work of Boole and continued by Lindenbaum, Tarski, Stone, McKinsey,
Mostowski, Henkin, was the main research subject of Helena Rasiowa.
Two very important developments in the algebraic study of logic were
the introduction by Lindenbaum and Tarski of the method of treating
equivalence classes of formulas as elements of an abstract algebraic
system, and the treatment of formulas as algebraic functions in certain
algebras originated by Lukasiewicz and Post with their generalization
of truth tables. Algebraic methods in investigations of intuitionistic
and modal logics were originated by Stone, Tarski and McKinsey. Helena
Rasiowa became very active in these areas in early fifties. Jointly
with Roman Sikorski, she presented the first algebraic proof of
G"odel's completeness theorem for classical predicate logic. Next,
she proved the analogous theorems for intuitionistic and modal logics
algebraically. Since then many logicians have employed algebraic
methods in investigations of logical calculi. Her first monograph
`The Mathematics of Metamathemathics' (Polish Science Publishers,
Warsaw 1963), joint with Roman Sikorski, contains a comprehensive
survey of algebraic theories of logical calculi. The algebraization
is presented of classical, intuitionistic, modal and positive logics.
The book concentrates on metalogical theorems concerning predicate
calculi of these logics and on investigation of elementary theories
based on these logics. In the next monograph `Algebraic Approach to
Non-Classical Logics' (Studies in Logic and the Foundations of
Mathematics, vol. 78, North Holland, Amsterdam 1974), Helena Rasiowa
developed a general theory of algebraization of logical systems.
Within the framework of this theory she presented algebraizations
of a number of non-classical logics: classical and positive implicative
logics, logics weaker than positive implicative logic, minimal logic,
positive logic with semi-negation, constructive logic with strong
negation, and multiple-valued Post logics.
  From the early seventies on, Helena Rasiowa became interested in
foundational problems in computation theory. She recognised that
theoretical computer science has represented an important source of
inspiration in development of logic. She initiated research on logics
of programs; algorithmic logic and its theory was developed under her
supervision. She was working on a theory of approximate reasoning and
developed various AI-oriented logical systems for modeling cognitive
processes.
  She was active in her work till the last days, during the past two
years she was working on a new monograph: `Algebraic Analysis of
Non-Classical First Order Logics'.
  Helena Rasiowa was the founder and the editor-in-chief of Fundamenta
Informaticae, collecting editor of Studia Logica, and associate editor
of the Journal of Approximate Reasoning. She received numerous honors
and awards, including Sierpinski medal, the title of Honorary Member
of the Polish Mathematical Society, the Stefan Mazurkiewicz Award of
the Polish Mathematical Society, and the First Class State Science
Award in Mathematics. She served as President of the Warsaw Division
of The Polish Mathematical Society and as Assessor of the Division of
Logic, Methodology, and Philosophy of Science of the International
Union of History and Philosophy of Science. She served the Association
for Symbolic Logic as a member of the Council. She was the Head of the
Council of the Polish Association of Logic and Philosophy of Science.
  Helena Rasiowa exerted a great influence on many logicians around
the world, her death is a great loss for the logic community.

  Ewa Orlowska.