Operations research
This or that
Four OR pairs students always mix up
Do you know the difference? Four pairs that cost marks every semester.
Quick check · tap an answer to continue
Lesson notes
Key points
- Slack / Surplus: Slack is unused resource in ≤ constraints; surplus is excess above a ≥ minimum.
- Basic / Non-basic: Basic variables can be nonzero in the tableau; non-basic variables are set to zero.
- Balanced / Unbalanced: Balanced transport has supply equal to demand; unbalanced needs a dummy row or column.
- Infeasible / Unbounded: Infeasible means no point satisfies all constraints; unbounded means the objective grows forever.
Takeaway: Infeasible: no answer. Unbounded: no limit. Know which is which.
Quick check: What do you call an LP with infinitely many optimal points?
- Alternative optima
- Degenerate solution
- Unbounded solution
Alternative optima occur when the objective is parallel to a binding constraint.
Lessons like this, for your syllabus.
Short narrated study videos written for your course, level and exam. Free to start.
Get lessons for your own syllabus