DOI: 10.4153/s0008439526102513 ISSN: 0008-4395

Disproofs of two conjectures concerning nondeficient numbers

John M. Campbell

Abstract

A positive integer n is said to be nondeficient if

σ ( n ) ≥ 2 n $\sigma (n) \geq 2n$ sigma left parenthesis n right parenthesis greater than or equals 2 n
. Letting the positive divisors of an integer
n > 1 $n> 1$ n greater than 1
be written as
1 = d 0 < d 1 < ⋯ < d k < d k + 1 = n $1 = d_0 < d_1 < \cdots < d_k < d_{k+1} = n$ 1 equals d 0 less than d 1 less than midline horizontal ellipsis less than d Subscript k Baseline less than d Subscript k plus 1 Baseline equals n
, and letting
S $\mathcal {S}$ script upper S
denote a set of integers, if there exist values
λ j ∈ S $\lambda _j \in \mathcal {S}$ lamda Subscript j Baseline element of script upper S
such that
1 + ∑ j = 1 k λ j d j = n $1 + \sum _{j=1}^{k} \lambda _j d_j = n$ 1 plus sigma summation Underscript j equals 1 Overscript k Endscripts lamda Subscript j Baseline d Subscript j Baseline equals n
, then n is said to be an
S $\mathcal {S}$ script upper S
-perfect number . Ross, in 2024, introduced the study of
S $\mathcal {S}$ script upper S
-perfect numbers and concluded with two conjectures that each concern both
{ − 1 , 1 } $\{ -1, 1 \}$ StartSet negative 1 comma 1 EndSet
-perfect numbers and nondeficient numbers. We disprove both of these conjectures.