# On stability of delay equations with positive and negative coefficients with applications

## TL;DR

This paper develops new explicit exponential stability conditions for linear delay differential equations with mixed positive and negative terms, and applies these results to analyze the local stability of Mackey--Glass type models.

## Contribution

It introduces novel explicit stability criteria for delay equations with mixed coefficients and applies them to biological models, extending existing stability analysis methods.

## Key findings

- Derived new exponential stability conditions for delay equations.
- Applied stability criteria to Mackey--Glass models.
- Established local stability results for specific biological delay models.

## Abstract

We obtain new explicit exponential stability conditions for linear scalar equations with positive and negative delayed terms $$ \dot{x}(t)+ \sum_{k=1}^m a_k(t)x(h_k(t))- \sum_{k=1}^l b_k(t)x(g_k(t))=0 $$ and its modifications, and apply them to investigate local stability of Mackey--Glass type models $$\dot{x}(t)=r(t)\left[\beta\frac{x(g(t))}{1+x^n(g(t))}-\gamma x(h(t))\right]$$ and $$\dot{x}(t)=r(t)\left[\beta\frac{x(g(t))}{1+x^n(h(t))}-\gamma x(t)\right].$$