The Subjunctive Particle να (No Infinitive)
Greek has NO infinitive. Where English uses “to …” (“I want TO write”), Greek uses να + a fully conjugated verb that AGREES with the subject: θέλω να γράψω (“I want to write”, literally “I-want that I-write”). να most often takes the perfective stem for a single act (να γράψω) - the same dependent stem as the future. The single biggest surprise for English speakers: να is not “to”, and there is no infinitive to reach for.
The rule
Greek has no infinitive. Where English uses “to …”, Greek uses να + a fully conjugated verb that agrees with the subject: θέλω να γράψω (“I want to write”, literally “I-want that I-write”), θέλει να γράψει (“he wants to write” - the second verb changes for the person). After να the perfective (dependent) stem is the default for a single act - να γράψω - the same stem the future uses. There is no frozen “to write” to reach for; always conjugate the second verb.