Comparison

ProofSketch vs Valve Explorer

Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.

Head to head

Map proof structure

Industrial Valves Reference

Free

📚 Education

No ratingsView app →

About

ProofSketch

Features

Read full description

ProofSketch helps you structure mathematical proofs through theorem cards, linked proof steps, lemmas, dependency maps, revision history, and PDF export. It does not generate proofs, verify correctness, provide hints, or evaluate accuracy.

About

Valve Explorer

Read full description

Valve Explorer is an educational reference for industrial and engineering valves. Learn valve types, applications, and terminology with quizzes and flashcards. Fully offline.

Screenshots

ProofSketch4 screens

Valve Explorer4 screens

Verdict

The call

ProofSketch and Valve Explorer are too close to call on the numbers: across 6 compared parameters — price, update cadence, ads and in-app purchases among them — neither pulls far enough ahead to decide it. What separates them is feature set and interface, not measurable difference.

Scored on Price · Rating · Positive reviews · Number of ratings · Update frequency · Ads · In-app purchases · Monetization · Best chart rank · Devices · Requires iOS

CostPrice · In-app purchases · Ads · Monetization

Both are free to download. Neither carries in-app purchases, so what you see is what you pay.

UpkeepUpdate frequency

ProofSketch ships an update every 5 days, Valve Explorer weekly. The most recent releases landed on September 21, 2026 and September 20, 2026 respectively.

ScorecardNo meaningful differences

ProofSketch versus Valve Explorer: the parameters behind the verdict, then further details
Parameter	ProofSketch	Valve Explorer
Price	Free	Free
Update frequency	Every 5 days — better	Weekly
Ads	No	No
In-app purchases	No	No
Devices	iPhone, iPad, iPod — better	iPhone, iPod
Requires iOS	13.0	13.0
Further details — not scored
Size	34 MB	57 MB
Age rating	4+	4+
Developer	Simge nur Karadag	Pham Van Thanh

In-app purchases

None

ProofSketch

No in-app purchases

None

Valve Explorer

No in-app purchases

Questions

Is ProofSketch free?

ProofSketch is free to download, with no in-app purchases.

Is Valve Explorer free?

Valve Explorer is free to download, with no in-app purchases.

Do ProofSketch or Valve Explorer have ads?

Neither ProofSketch nor Valve Explorer shows ads.

Which is updated more often, ProofSketch or Valve Explorer?

ProofSketch ships an update every 5 days, and Valve Explorer weekly. Most recently, ProofSketch was updated on September 21, 2026 and Valve Explorer on September 20, 2026.