# Ittai Abraham et al. - Partial Synchrony Variants (Highlights)
## Metadata
**Review**:: [readwise.io](https://readwise.io/bookreview/58510989)
**Source**:: #from/readwise #from/reader
**Zettel**:: #zettel/fleeting
**Status**:: #x
**Authors**:: [[Ittai Abraham]], [[Yuval Efron]], [[Kartik Nayak]], [[Ling Ren]]
**Full Title**:: Partial Synchrony Variants
**Category**:: #articles #readwise/articles
**Category Icon**:: 📰
**URL**:: [decentralizedthoughts.github.io](https://decentralizedthoughts.github.io/2025-12-19-cc-under-harsh-ps/)
**Host**:: [[decentralizedthoughts.github.io]]
**Highlighted**:: [[2026-02-23]]
**Created**:: [[2026-03-02]]
## Highlights
- **Bounded Partial Synchrony (BPS)**: A message sent at time tt arrives by time at most maxt,GST+Δmaxt,GST+Δ ([View Highlight](https://read.readwise.io/read/01kj4992jmf7zka09qbwyevde5)) ^990825601
This definition implicitly assumes that messages sent before GST are delayed but not lost, and that they all arrive by time GST+Δ.
- **Unbounded Partial Synchrony (UPS)**: A message sent at time t≥GSTt≥GST arrives at time at most t+Δt+Δ. Other messages may have unbounded delay. ([View Highlight](https://read.readwise.io/read/01kj49bqd8w4wvrc6ge2jzqgt1)) ^990825660
UPS allows messages sent before GST to have unbounded delay
- **Lossy Partial Synchrony (LPS)**: A message sent at time t≥GSTt≥GST arrives at time at most t+Δt+Δ. Other messages may have unbounded delay or may be dropped. ([View Highlight](https://read.readwise.io/read/01kj49c1s2ge113m90tkveb8c4)) ^990825666
LPS models systems where the network before GST is so unreliable that messages may be lost.