TY - JOUR

T1 - Shrinkage of de Morgan formulae under restriction

AU - Paterson, Michael S.

AU - Zwick, Uri

PY - 1993

Y1 - 1993

N2 - It is shown that a random restriction leaving only a fraction ϵ of the input variables unassigned reduces the expected de Morgan formula size of the induced function by a factor of O(E(5−√2)/2) = O(ϵ1.63). (A de Morgan, or unate, formula is a formula over the basis {∧, ∨, ¬}.) This improves a long‐standing result of O(ϵ1.5) by Subbotovskaya and a recent improvement to O(ϵ(21−√73)/8) = O(ϵ1.55) by Nisan and Impagliazzo. The New exponent yields an increased lower bound of n(7−√3)/2−o(1) = Ω(n2.63) for the de Morgan formula size of a function in P defined by Andreev. This is the largest formula size lower bound known, even for functions in NP. © 1993 John Wiley & Sons, Inc.

AB - It is shown that a random restriction leaving only a fraction ϵ of the input variables unassigned reduces the expected de Morgan formula size of the induced function by a factor of O(E(5−√2)/2) = O(ϵ1.63). (A de Morgan, or unate, formula is a formula over the basis {∧, ∨, ¬}.) This improves a long‐standing result of O(ϵ1.5) by Subbotovskaya and a recent improvement to O(ϵ(21−√73)/8) = O(ϵ1.55) by Nisan and Impagliazzo. The New exponent yields an increased lower bound of n(7−√3)/2−o(1) = Ω(n2.63) for the de Morgan formula size of a function in P defined by Andreev. This is the largest formula size lower bound known, even for functions in NP. © 1993 John Wiley & Sons, Inc.

UR - http://www.scopus.com/inward/record.url?scp=84990671465&partnerID=8YFLogxK

U2 - 10.1002/rsa.3240040203

DO - 10.1002/rsa.3240040203

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AN - SCOPUS:84990671465

SN - 1042-9832

VL - 4

SP - 135

EP - 150

JO - Random Structures and Algorithms

JF - Random Structures and Algorithms

IS - 2

ER -