  This volume contains papers presented at the Ninth International Symposium on
Symbolic Computation in Software Science, SCSS 2021.
  Symbolic Computation is the science of computing with symbolic objects
(terms, formulae, programs, representations of algebraic objects, etc.).
Powerful algorithms have been developed during the past decades for the major
subareas of symbolic computation: computer algebra and computational logic.
These algorithms and methods are successfully applied in various fields,
including software science, which covers a broad range of topics about software
construction and analysis.
  Meanwhile, artificial intelligence methods and machine learning algorithms
are widely used nowadays in various domains and, in particular, combined with
symbolic computation. Several approaches mix artificial intelligence and
symbolic methods and tools deployed over large corpora to create what is known
as cognitive systems. Cognitive computing focuses on building systems that
interact with humans naturally by reasoning, aiming at learning at scale.
  The purpose of SCSS is to promote research on theoretical and practical
aspects of symbolic computation in software science, combined with modern
artificial intelligence techniques. These proceedings contain the keynote paper
by Bruno Buchberger and ten contributed papers. Besides, the conference program
included three invited talks, nine short and work-in-progress papers, and a
special session on computer algebra and computational logic. Due to the
COVID-19 pandemic, the symposium was held completely online. It was organized
by the Research Institute for Symbolic Computation (RISC) of the Johannes
Kepler University Linz on September 8--10, 2021.
