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REPORTS > AUTHORS > DETLEF SIELING:
All reports by Author Detlef Sieling:

TR02-054 | 5th September 2002
Detlef Sieling

Minimization of Decision Trees is Hard to Approximate

Decision trees are representations of discrete functions with widespread applications in, e.g., complexity theory and data mining and exploration. In these areas it is important to obtain decision trees of small size. The minimization problem for decision trees is known to be NP-hard. In this paper the problem is shown ... more >>>


TR01-017 | 14th February 2001
Petr Savicky, Detlef Sieling

A Hierarchy Result for Read-Once Branching Programs with Restricted Parity Nondeterminism

Restricted branching programs are considered in complexity theory in
order to study the space complexity of sequential computations and
in applications as a data structure for Boolean functions. In this
paper (\oplus,k)-branching programs and (\vee,k)-branching
programs are considered, i.e., branching programs starting with a
... more >>>


TR99-019 | 7th June 1999
Detlef Sieling

Lower Bounds for Linear Transformed OBDDs and FBDDs


Linear Transformed Ordered Binary Decision Diagrams (LTOBDDs) have
been suggested as a generalization of OBDDs for the representation and
manipulation of Boolean functions. Instead of variables as in the
case of OBDDs parities of variables may be tested at the nodes of an
LTOBDD. By this extension it is ... more >>>


TR99-001 | 4th January 1999
Detlef Sieling

The Complexity of Minimizing FBDDs

Revisions: 1

Free Binary Decision Diagrams (FBDDs) are a data structure
for the representation and manipulation of Boolean functions.
Efficient algorithms for most of the important operations are known if
only FBDDs respecting a fixed graph ordering are considered. However,
the size of such an FBDD may strongly depend on the chosen ... more >>>


TR98-045 | 17th July 1998
Detlef Sieling

A Separation of Syntactic and Nonsyntactic (1,+k)-Branching Programs

For (1,+k)-branching programs and read-k-times branching
programs syntactic and nonsyntactic variants can be distinguished. The
nonsyntactic variants correspond in a natural way to sequential
computations with restrictions on reading the input while lower bound
proofs are easier or only known for the syntactic variants. In this
paper it is shown ... more >>>


TR98-001 | 17th December 1997
Detlef Sieling

On the Existence of Polynomial Time Approximation Schemes for OBDD Minimization

Revisions: 1

The size of Ordered Binary Decision Diagrams (OBDDs) is
determined by the chosen variable ordering. A poor choice may cause an
OBDD to be too large to fit into the available memory. The decision
variant of the variable ordering problem is known to be
NP-complete. We strengthen this result by ... more >>>


TR95-002 | 1st January 1995
Detlef Sieling

New Lower Bounds and Hierarchy Results for Restricted Branching Programs

In unrestricted branching programs all variables may be tested
arbitrarily often on each path. But exponential lower bounds are only
known, if on each path the number of tests of each variable is bounded
(Borodin, Razborov and Smolensky (1993)). We examine branching programs
in which for each path the ... more >>>


TR94-026 | 12th December 1994
Beate Bollig, Martin Sauerhoff, Detlef Sieling, Ingo Wegener

On the Power of Different Types of Restricted Branching Programs


Almost the same types of restricted branching programs (or
binary decision diagrams BDDs) are considered in complexity
theory and in applications like hardware verification. These
models are read-once branching programs (free BDDs) and certain
types of oblivious branching programs (ordered and indexed BDDs
with k layers). The complexity of ... more >>>




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